Fix build on Windows

README.md

@@ -34,16 +34,16 @@ You can find the latest development version continuously deployed to
 ## ✨ Key Features
 
 ✅ **Decentralized & Federated** – No central authority; works across Matrix
-homeservers.  
-✅ **End-to-End Encrypted** – Secure and private calls.  
+homeservers.
+✅ **End-to-End Encrypted** – Secure and private calls.
 ✅ **Standalone, Widget & Component Mode** – Use as an independent app, embed
 in Matrix clients as a widget, or (experimentally) mount it as a React component
-inside your own application.  
-✅ **WebRTC-based** – No additional software required.  
+inside your own application.
+✅ **WebRTC-based** – No additional software required.
 ✅ **Scalable with LiveKit** – Supports large meetings via SFU
-([MSC4195: MatrixRTC using LiveKit backend](https://github.com/hughns/matrix-spec-proposals/blob/hughns/matrixrtc-livekit/proposals/4195-matrixrtc-livekit.md)).  
+([MSC4195: MatrixRTC using LiveKit backend](https://github.com/hughns/matrix-spec-proposals/blob/hughns/matrixrtc-livekit/proposals/4195-matrixrtc-livekit.md)).
 ✅ **Raise Hand** – Participants can signal when they want to speak, helping to
-organize the flow of the meeting.  
+organize the flow of the meeting.
 ✅ **Emoji Reactions** – Users can react with emojis 👍️ 🎉 👏 🤘, adding
 engagement and interactivity to the conversation.
 
@@ -309,6 +309,23 @@ root. The host imports the component from
 `react-dom`, `matrix-js-sdk` and `livekit-client` itself, since the bundle leaves
 them external.
 
+The component is large, and a host will usually load it lazily, only once a
+call is shown. Everything a host needs in order to talk about a call before
+then is also exported
+from `@element-hq/element-call-component/api` (a small entry point that does not
+load the component).
+
+- props and the types they are made of
+- the handle
+- the host bridge
+- `UserIntent`
+- `HeaderStyle`
+- `BackgroundStyle` enums
+- `configurationForIntent`, the defaults each intent implies
+  Import from it wherever a value such as
+  `BackgroundStyle.Solid` is needed on a path that must stay light; the main
+  entry point re-exports all of it too.
+
 ### Backend
 
 A docker compose file `docker-compose-dev.yml` is provided to start the

component/api.ts

@@ -0,0 +1,124 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+/**
+ * EXPERIMENTAL
+ *
+ * What a host needs in order to talk about Element Call, without Element Call:
+ * the component's props and the types they are made of, the handle and the
+ * host bridge, the intents a call can be started with and the configuration
+ * each implies.
+ *
+ * This is an entry point of its own, `@element-hq/element-call-component/api`,
+ * so that a host can import it on a path that must stay light — a call model
+ * that needs `BackgroundStyle.Solid` as a value, say — and load the component
+ * itself, and everything it brings, only when a call is shown. The main entry
+ * point re-exports all of it, so a host that does not care may import
+ * everything from there.
+ *
+ * Nothing in here may reach anything that is not a type or a constant: the
+ * point of this module is what it does not import.
+ */
+
+import type { Ref } from "react";
+import type { MatrixClient } from "matrix-js-sdk";
+
+import type { UrlProperties } from "../src/UrlParams";
+import type { ElementCallHandle, ElementCallHostBridge } from "./host";
+import {
+  BackgroundStyle,
+  configurationForIntent,
+  HeaderStyle,
+  type UrlConfiguration,
+  UserIntent,
+} from "../src/UrlConfiguration";
+
+// How the host and Element Call talk to each other, and what they say
+export type { ElementCallHandle, ElementCallHostBridge } from "./host";
+export type { DeviceMuteRequest, DeviceMuteState } from "../src/HostBridge";
+export type { JoinCallData } from "../src/widget";
+// The deployment-wide configuration, as distinct from ElementCallConfiguration
+// below, which is per call
+export type { ConfigOptions } from "../src/config/ConfigOptions";
+// The values that appear in ElementCallConfiguration and in the intent, and
+// what each intent means by default
+export {
+  BackgroundStyle,
+  configurationForIntent,
+  HeaderStyle,
+  type UrlConfiguration,
+  UserIntent,
+};
+
+/**
+ * How Element Call should behave. Everything is optional; anything left out
+ * takes the default that {@link ElementCallProps.intent} implies.
+ *
+ * This is the behaviour a widget can be configured with through its URL, plus
+ * the one fact about the call a host has a say in here, the background. The
+ * rest of what a widget's URL carries — who the user is, how to reach the
+ * homeserver, where to report analytics, the shared secret of a room that is
+ * encrypted with one — a component host supplies by other routes, or not at
+ * all; and what can change while the call is running, the theme and the
+ * language, is a prop of its own.
+ */
+export type ElementCallConfiguration = Partial<UrlConfiguration> &
+  Partial<Pick<UrlProperties, "background">>;
+
+export interface ElementCallProps {
+  /**
+   * The client to place the call with. Element Call does not authenticate
+   * anyone or manage a session of its own; this one is the host's.
+   */
+  client: MatrixClient;
+  /** The room to call in. The host's client must already know about it. */
+  roomId: string;
+  /**
+   * What the user asked for — whether they started the call or joined one that
+   * was already running, and whether it is a call in a group or a DM. Element
+   * Call decides what each of those means: whether to show the lobby first,
+   * whether to ring, and so on.
+   *
+   * Defaults to joining an existing group call, which is the most conservative
+   * reading, but a host that knows which button the user pressed should say so.
+   */
+  intent?: UserIntent;
+  /**
+   * How Element Call should behave, overriding whatever {@link intent} implies.
+   * A host that finds itself setting a lot of these probably wants a different
+   * intent instead.
+   *
+   * Compared by value, so it is fine to write this inline; only a change to
+   * what it says restarts anything.
+   */
+  config?: ElementCallConfiguration;
+  /**
+   * What Element Call tells the host while the call is running: that the user
+   * has joined or hung up, that it would like to be kept on screen, and so on.
+   * Without one, Element Call assumes nobody is listening.
+   */
+  hostBridge?: ElementCallHostBridge;
+  /**
+   * What the host tells Element Call: to hang up, to mute, to join. Available
+   * once the component has rendered.
+   */
+  ref?: Ref<ElementCallHandle>;
+  /**
+   * The theme to show Element Call in, `light` or `dark`. Left out, Element
+   * Call picks. Changes take effect at once, and cost nothing else.
+   */
+  theme?: string;
+  /**
+   * The language to show Element Call in, as a BCP 47 tag: one of the
+   * `supportedLanguages` the main entry point exports, or something that falls
+   * back to one (`de-AT` to `de`). Left out, the browser's language is used.
+   *
+   * Translations are one thing shared by every Element Call on the page, so
+   * the most recently set language wins for all of them.
+   */
+  language?: string;
+}

component/index.tsx

@@ -36,14 +36,12 @@ import {
   type FC,
   type JSX,
   type ReactNode,
-  type Ref,
   useEffect,
   useLayoutEffect,
   useMemo,
   useRef,
   useState,
 } from "react";
-import { type MatrixClient } from "matrix-js-sdk";
 import { logger } from "matrix-js-sdk/lib/logger";
 import { I18nextProvider } from "react-i18next";
 import { TooltipProvider } from "@vector-im/compound-web";
@@ -62,10 +60,8 @@ import { RootElementProvider, useRootElement } from "../src/RootElementContext";
 import {
   configurationForIntent,
   componentProperties,
-  type UrlConfiguration,
   type UrlParams,
   UrlParamsProvider,
-  type UrlProperties,
   UserIntent,
   useUrlParams,
 } from "../src/UrlParams";
@@ -79,102 +75,16 @@ import { i18n } from "../src/utils/i18n";
 import { useTheme } from "../src/useTheme";
 import { useStableValue } from "../src/useStableValue";
 import styles from "./ElementCall.module.css";
-import {
-  type ElementCallHandle,
-  type ElementCallHostBridge,
-  useComponentHostBridge,
-} from "./host";
+import { useComponentHostBridge } from "./host";
+import { type ElementCallProps } from "./api";
 import { supportedLanguages, translationsBackend } from "./localization";
 
 // The languages Element Call can be shown in
 export { supportedLanguages } from "./localization";
-
-// How the host and Element Call talk to each other, and what they say
-export { type ElementCallHandle, type ElementCallHostBridge } from "./host";
-export {
-  type DeviceMuteRequest,
-  type DeviceMuteState,
-} from "../src/HostBridge";
-export { type JoinCallData } from "../src/widget";
-// The deployment-wide configuration, as distinct from ElementCallConfiguration
-// above, which is per call
-export { type ConfigOptions } from "../src/config/ConfigOptions";
-// The values that appear in ElementCallConfiguration and in the intent
-export {
-  BackgroundStyle,
-  HeaderStyle,
-  UserIntent,
-  type UrlConfiguration,
-} from "../src/UrlParams";
-
-/**
- * How Element Call should behave. Everything is optional; anything left out
- * takes the default that {@link ElementCallProps.intent} implies.
- *
- * This is the behaviour a widget can be configured with through its URL, plus
- * the one fact about the call a host has a say in here, the background. The
- * rest of what a widget's URL carries — who the user is, how to reach the
- * homeserver, where to report analytics, the shared secret of a room that is
- * encrypted with one — a component host supplies by other routes, or not at
- * all; and what can change while the call is running, the theme and the
- * language, is a prop of its own.
- */
-export type ElementCallConfiguration = Partial<UrlConfiguration> &
-  Partial<Pick<UrlProperties, "background">>;
-
-export interface ElementCallProps {
-  /**
-   * The client to place the call with. Element Call does not authenticate
-   * anyone or manage a session of its own; this one is the host's.
-   */
-  client: MatrixClient;
-  /** The room to call in. The host's client must already know about it. */
-  roomId: string;
-  /**
-   * What the user asked for — whether they started the call or joined one that
-   * was already running, and whether it is a call in a group or a DM. Element
-   * Call decides what each of those means: whether to show the lobby first,
-   * whether to ring, and so on.
-   *
-   * Defaults to joining an existing group call, which is the most conservative
-   * reading, but a host that knows which button the user pressed should say so.
-   */
-  intent?: UserIntent;
-  /**
-   * How Element Call should behave, overriding whatever {@link intent} implies.
-   * A host that finds itself setting a lot of these probably wants a different
-   * intent instead.
-   *
-   * Compared by value, so it is fine to write this inline; only a change to
-   * what it says restarts anything.
-   */
-  config?: ElementCallConfiguration;
-  /**
-   * What Element Call tells the host while the call is running: that the user
-   * has joined or hung up, that it would like to be kept on screen, and so on.
-   * Without one, Element Call assumes nobody is listening.
-   */
-  hostBridge?: ElementCallHostBridge;
-  /**
-   * What the host tells Element Call: to hang up, to mute, to join. Available
-   * once the component has rendered.
-   */
-  ref?: Ref<ElementCallHandle>;
-  /**
-   * The theme to show Element Call in, `light` or `dark`. Left out, Element
-   * Call picks. Changes take effect at once, and cost nothing else.
-   */
-  theme?: string;
-  /**
-   * The language to show Element Call in, as a BCP 47 tag: one of
-   * {@link supportedLanguages}, or something that falls back to one (`de-AT`
-   * to `de`). Left out, the browser's language is used.
-   *
-   * Translations are one thing shared by every Element Call on the page, so
-   * the most recently set language wins for all of them.
-   */
-  language?: string;
-}
+// Everything a host needs to talk about Element Call — the props, the handle,
+// the host bridge, the intents and what each means — also available without
+// the component itself from `@element-hq/element-call-component/api`
+export * from "./api";
 
 /**
  * Prepares the things Element Call needs before it can be shown: translations,

component/package.json

@@ -25,6 +25,10 @@
       "types": "./dist/types/component/index.d.ts",
       "default": "./dist/element-call.js"
     },
+    "./api": {
+      "types": "./dist/types/component/api.d.ts",
+      "default": "./dist/api.js"
+    },
     "./style.css": "./dist/element-call.css"
   },
   "sideEffects": [

component/tsconfig.build.json

@@ -13,8 +13,8 @@
     "rootDir": "..",
     "outDir": "./dist/types"
   },
-  // The entry point, plus the ambient declarations (CSS modules, `?react` SVGs,
-  // `import.meta.env`, …) that the sources it reaches rely on.
-  "include": ["./index.tsx", "../src/@types/*.d.ts"],
+  // The entry points, plus the ambient declarations (CSS modules, `?react` SVGs,
+  // `import.meta.env`, …) that the sources they reach rely on.
+  "include": ["./index.tsx", "./api.ts", "../src/@types/*.d.ts"],
   "exclude": []
 }

docs/agents/architecture.md

@@ -76,4 +76,7 @@ Code that builds in only one is a bug.
 - `build:component` — `@element-hq/element-call-component`, sources in `component/`
   (its own pnpm project; run pnpm from the repo root). Host API is in the README;
   `pnpm lint:externals` rejects an import of a `react` / `react-dom` /
-  `matrix-js-sdk` / `livekit-client` subpath the externals list omits.
+  `matrix-js-sdk` / `livekit-client` subpath the externals list omits. Two entry
+  points: `index.tsx` (the component) and `api.ts` (types, enums and
+  `configurationForIntent`, for a host that must not load the component). `api.ts`
+  may only reach types and constants — `src/UrlConfiguration.ts`, not `UrlParams`.

package.json

@@ -8,7 +8,7 @@
     "dev:embedded": "vite --config vite-embedded.config.js",
     "dev:component": "vite --config vite-component-dev.config.ts",
     "build": "pnpm build:full",
-    "build:full": "NODE_OPTIONS=--max-old-space-size=16384 vite build",
+    "build:full": "node --max-old-space-size=16384 node_modules/vite/bin/vite.js build",
     "build:full:production": "pnpm build:full",
     "build:full:development": "pnpm build:full --mode development",
     "build:embedded": "pnpm build:full --config vite-embedded.config.js",
@@ -83,7 +83,7 @@
     "@types/sdp-transform": "^2.4.5",
     "@typescript-eslint/utils": "^8.61.0",
     "@use-gesture/react": "^10.2.11",
-    "@vector-im/compound-design-tokens": "^11.0.0",
+    "@vector-im/compound-design-tokens": "^10.0.0",
     "@vector-im/compound-web": "^10.0.0",
     "@vitejs/plugin-react": "^6.0.2",
     "@vitest/browser-playwright": "^4.1.5",

pnpm-lock.yaml

@@ -131,11 +131,11 @@ importers:
         specifier: ^10.2.11
         version: 10.3.1(react@19.2.8)
       '@vector-im/compound-design-tokens':
-        specifier: ^11.0.0
-        version: 11.0.0(@types/react@19.2.18)(react@19.2.8)
+        specifier: ^10.0.0
+        version: 10.2.4(@types/react@19.2.18)(react@19.2.8)
       '@vector-im/compound-web':
         specifier: ^10.0.0
-        version: 10.0.1(@fontsource/inconsolata@5.3.0)(@fontsource/inter@5.3.0)(@types/react-dom@19.2.5(@types/react@19.2.18))(@types/react@19.2.18)(@vector-im/compound-design-tokens@11.0.0(@types/react@19.2.18)(react@19.2.8))(react-dom@19.2.8(react@19.2.8))(react@19.2.8)
+        version: 10.0.1(@fontsource/inconsolata@5.3.0)(@fontsource/inter@5.3.0)(@types/react-dom@19.2.5(@types/react@19.2.18))(@types/react@19.2.18)(@vector-im/compound-design-tokens@10.2.4(@types/react@19.2.18)(react@19.2.8))(react-dom@19.2.8(react@19.2.8))(react@19.2.8)
       '@vitejs/plugin-react':
         specifier: ^6.0.2
         version: 6.1.1(@rolldown/plugin-babel@0.2.3(@babel/core@7.29.7(supports-color@7.2.0))(@babel/runtime@8.0.0)(rolldown@1.2.7)(vite@8.2.2(@types/node@24.13.3)(esbuild@0.28.2)(jiti@2.7.0)(sass@1.103.1)(terser@5.46.1)(yaml@2.9.0)))(babel-plugin-react-compiler@1.0.0)(vite@8.2.2(@types/node@24.13.3)(esbuild@0.28.2)(jiti@2.7.0)(sass@1.103.1)(terser@5.46.1)(yaml@2.9.0))
@@ -3229,8 +3229,8 @@ packages:
     peerDependencies:
       react: '>= 16.8.0'
 
-  '@vector-im/compound-design-tokens@11.0.0':
-    resolution: {integrity: sha512-pWz0Q67Xbo8gwzaTeFbTTcM6i29ju6PR7SqyuExr2nIV3j9K785cOInft8FA2CM7PEapkr6TRtJKR/4xtWh2RA==}
+  '@vector-im/compound-design-tokens@10.2.4':
+    resolution: {integrity: sha512-2aCjhSvJxktPWnvh5s9Xdc0Rd76AfHqbDbN4QjOxo2VIac6zYdLyQbxMUQ5ZeoR9G3vAxILd0H1UvApRfMilpQ==}
     peerDependencies:
       '@adobe/leonardo-contrast-colors': ^1.0.0
       '@types/react': '*'
@@ -8695,12 +8695,12 @@ snapshots:
       '@use-gesture/core': 10.3.1
       react: 19.2.8
 
-  '@vector-im/compound-design-tokens@11.0.0(@types/react@19.2.18)(react@19.2.8)':
+  '@vector-im/compound-design-tokens@10.2.4(@types/react@19.2.18)(react@19.2.8)':
     optionalDependencies:
       '@types/react': 19.2.18
       react: 19.2.8
 
-  '@vector-im/compound-web@10.0.1(@fontsource/inconsolata@5.3.0)(@fontsource/inter@5.3.0)(@types/react-dom@19.2.5(@types/react@19.2.18))(@types/react@19.2.18)(@vector-im/compound-design-tokens@11.0.0(@types/react@19.2.18)(react@19.2.8))(react-dom@19.2.8(react@19.2.8))(react@19.2.8)':
+  '@vector-im/compound-web@10.0.1(@fontsource/inconsolata@5.3.0)(@fontsource/inter@5.3.0)(@types/react-dom@19.2.5(@types/react@19.2.18))(@types/react@19.2.18)(@vector-im/compound-design-tokens@10.2.4(@types/react@19.2.18)(react@19.2.8))(react-dom@19.2.8(react@19.2.8))(react@19.2.8)':
     dependencies:
       '@floating-ui/react': 0.27.20(react-dom@19.2.8(react@19.2.8))(react@19.2.8)
       '@floating-ui/react-dom': 2.1.9(react-dom@19.2.8(react@19.2.8))(react@19.2.8)
@@ -8712,7 +8712,7 @@ snapshots:
       '@radix-ui/react-progress': 1.1.16(@types/react-dom@19.2.5(@types/react@19.2.18))(@types/react@19.2.18)(react-dom@19.2.8(react@19.2.8))(react@19.2.8)
       '@radix-ui/react-separator': 1.1.15(@types/react-dom@19.2.5(@types/react@19.2.18))(@types/react@19.2.18)(react-dom@19.2.8(react@19.2.8))(react@19.2.8)
       '@radix-ui/react-slot': 1.3.3(@types/react@19.2.18)(react@19.2.8)
-      '@vector-im/compound-design-tokens': 11.0.0(@types/react@19.2.18)(react@19.2.8)
+      '@vector-im/compound-design-tokens': 10.2.4(@types/react@19.2.18)(react@19.2.8)
       classnames: 2.5.1
       react: 19.2.8
       vaul: 1.1.2(@types/react-dom@19.2.5(@types/react@19.2.18))(@types/react@19.2.18)(react-dom@19.2.8(react@19.2.8))(react@19.2.8)

src/UrlConfiguration.ts

@@ -0,0 +1,242 @@
+/*
+Copyright 2022-2024 New Vector Ltd.
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+/**
+ * How Element Call can be told to behave, and what each intent means.
+ *
+ * Kept apart from {@link UrlParams} on purpose: everything here is constants,
+ * types and one function of them, so that a host of the component can import
+ * these — the enums it needs as values, the defaults an intent implies — without
+ * loading Element Call itself. UrlParams, which reads them from a URL, needs
+ * the router, the config and the rest of the app; this module must not.
+ * `component/api.ts` is built from it as an entry point of its own.
+ */
+
+import {
+  type RTCCallIntent,
+  type RTCNotificationType,
+} from "matrix-js-sdk/lib/matrixrtc";
+
+import { platform } from "./Platform";
+
+export enum UserIntent {
+  StartNewCall = "start_call",
+  JoinExistingCall = "join_existing",
+  StartNewCallVoice = "start_call_voice",
+  JoinExistingCallVoice = "join_existing_voice",
+  StartNewCallDM = "start_call_dm",
+  StartNewCallDMVoice = "start_call_dm_voice",
+  JoinExistingCallDM = "join_existing_dm",
+  JoinExistingCallDMVoice = "join_existing_dm_voice",
+  Unknown = "unknown",
+}
+
+export enum HeaderStyle {
+  None = "none",
+  Standard = "standard",
+  AppBar = "app_bar",
+}
+
+export enum BackgroundStyle {
+  Solid = "solid",
+  Gradient = "gradient",
+}
+
+/**
+ * The configuration for the app, which can be set via URL parameters.
+ * Those property are different to the UrlProperties, since they are all optional
+ * and configure the behavior of the app. Their value is the same if EC is used in
+ * the same context but with different accounts/users.
+ *
+ * Their defaults can be controlled by the `intent` property.
+ */
+export interface UrlConfiguration {
+  /**
+   * Whether the app should keep the user confined to the current call/room.
+   */
+  confineToRoom: boolean;
+  /**
+   * Whether the app should pause before joining the call until it sees an
+   * io.element.join widget action, allowing it to be preloaded.
+   */
+  preload: boolean;
+  /**
+   * The style of headers to show. "standard" is the default arrangement, "none"
+   * hides the header entirely, and "app_bar" produces a header with a back
+   * button like you might see in mobile apps. The callback for the back button
+   * is window.controls.onBackButtonPressed.
+   */
+  header: HeaderStyle;
+  /**
+   * Whether the controls should be shown. For screen recording no controls can be desired.
+   */
+  showControls: boolean;
+  /**
+   * Whether to hide the screen-sharing button.
+   */
+  hideScreensharing: boolean;
+
+  /**
+   * Whether the app is allowed to use fallback STUN servers for ICE in case the
+   * user's homeserver doesn't provide any.
+   */
+  allowIceFallback: boolean;
+
+  /**
+   * Whether the app should use per participant keys for E2EE.
+   */
+  perParticipantE2EE: boolean;
+  /**
+   * Whether the global JS controls for audio output devices should be enabled,
+   * allowing the list of output devices to be controlled by the app hosting
+   * Element Call.
+   */
+  controlledAudioDevices: boolean;
+  /**
+   * Setting this flag skips the lobby and brings you in the call directly.
+   * In the widget this can be combined with preload to pass the device settings
+   * with the join widget action.
+   */
+  skipLobby: boolean;
+  /**
+   * Setting this flag makes element call show the lobby after leaving a call.
+   * This is useful for video rooms.
+   */
+  returnToLobby: boolean;
+  /**
+   * Whether and what type of notification EC should send, when the user joins the call.
+   */
+  sendNotificationType?: RTCNotificationType;
+  /**
+   * Whether the app should automatically leave the call when there
+   * is no one left in the call.
+   * This is one part to make the call matrixRTC session behave like a telephone call.
+   */
+  autoLeaveWhenOthersLeft: boolean;
+
+  /**
+   * If the client should behave like it is awaiting an answer if a notification was sent (wait for call pick up).
+   * This is a no-op if not combined with sendNotificationType.
+   *
+   * This entails:
+   *  - show ui that it is awaiting an answer
+   *  - play a sound that indicates that it is awaiting an answer
+   *  - auto-dismiss the call widget once the notification lifetime expires on the receivers side.
+   */
+  waitForCallPickup: boolean;
+
+  /**
+   * Whether to enable echo cancellation for audio capture.
+   * Defaults to true.
+   */
+  echoCancellation?: boolean;
+  /**
+   * Whether to enable noise suppression for audio capture.
+   * Defaults to true.
+   */
+  noiseSuppression?: boolean;
+
+  callIntent?: RTCCallIntent;
+}
+
+// If you need to add a new flag to this interface, prefer a name that describes
+// a specific behavior (such as 'confineToRoom'), rather than one that describes
+// the situations that call for this behavior ('isEmbedded'). This makes it
+// clearer what each flag means, and helps us avoid coupling Element Call's
+// behavior to the needs of specific consumers.
+
+/**
+ * The configuration implied by what the user meant to do — if they pressed a
+ * Start Call button this would be `start_call`, and if they pressed Join Call,
+ * `join_existing`.
+ *
+ * These are platform-specific defaults, so that a host can start a call by
+ * saying what the user asked for rather than by setting every parameter itself,
+ * and so that what each intent means is Element Call's decision, made in one
+ * place. A host that wants something else states it alongside the intent.
+ *
+ * {@link UserIntent.Unknown} means no intent was stated, and gives the
+ * standalone app's defaults: Element Call owns the whole page, so it offers the
+ * way out of the room that a hosted call must not.
+ */
+export function configurationForIntent(intent: UserIntent): UrlConfiguration {
+  // Only constants and `platform` here, so that this depends on nothing but
+  // the intent.
+  let preset: UrlConfiguration = {
+    confineToRoom: true,
+    preload: false,
+    header: platform === "desktop" ? HeaderStyle.None : HeaderStyle.AppBar,
+    showControls: true,
+    hideScreensharing: false,
+    allowIceFallback: true,
+    perParticipantE2EE: true,
+    controlledAudioDevices: platform === "desktop" ? false : true,
+    skipLobby: true,
+    returnToLobby: false,
+    sendNotificationType: "notification",
+    autoLeaveWhenOthersLeft: false,
+    waitForCallPickup: false,
+  };
+  switch (intent) {
+    case UserIntent.StartNewCall:
+      preset.skipLobby = false;
+      preset.callIntent = "video";
+      break;
+    case UserIntent.JoinExistingCall:
+      // On desktop this will be overridden based on which button was used to join the call
+      preset.skipLobby = false;
+      preset.callIntent = "video";
+      break;
+    case UserIntent.StartNewCallVoice:
+      preset.skipLobby = false;
+      preset.callIntent = "audio";
+      break;
+    case UserIntent.JoinExistingCallVoice:
+      // On desktop this will be overridden based on which button was used to join the call
+      preset.skipLobby = false;
+      preset.callIntent = "audio";
+      break;
+    case UserIntent.StartNewCallDMVoice:
+      preset.callIntent = "audio";
+    // Fall through
+    case UserIntent.StartNewCallDM:
+      preset.skipLobby = true;
+      preset.sendNotificationType = "ring";
+      preset.autoLeaveWhenOthersLeft = true;
+      preset.waitForCallPickup = true;
+      preset.callIntent = preset.callIntent ?? "video";
+      break;
+    case UserIntent.JoinExistingCallDMVoice:
+      preset.callIntent = "audio";
+    // Fall through
+    case UserIntent.JoinExistingCallDM:
+      // On desktop this will be overridden based on which button was used to join the call
+      preset.skipLobby = true;
+      preset.autoLeaveWhenOthersLeft = true;
+      preset.callIntent = preset.callIntent ?? "video";
+      break;
+    // Non widget usecase defaults
+    default:
+      preset = {
+        confineToRoom: false,
+        preload: false,
+        header: HeaderStyle.Standard,
+        showControls: true,
+        hideScreensharing: false,
+        allowIceFallback: false,
+        perParticipantE2EE: false,
+        controlledAudioDevices: false,
+        skipLobby: false,
+        returnToLobby: false,
+        sendNotificationType: undefined,
+        autoLeaveWhenOthersLeft: false,
+        waitForCallPickup: false,
+      };
+  }
+  return preset;
+}

src/UrlParams.ts

@@ -9,47 +9,36 @@ Please see LICENSE in the repository root for full details.
 import { createContext, use, useMemo } from "react";
 import { useLocation } from "react-router-dom";
 import { logger } from "matrix-js-sdk/lib/logger";
-import {
-  type RTCCallIntent,
-  type RTCNotificationType,
-} from "matrix-js-sdk/lib/matrixrtc";
 import { pickBy } from "lodash-es";
 
 import { Config } from "./config/Config";
 import { type EncryptionSystem } from "./e2ee/sharedKeyManagement";
 import { E2eeType } from "./e2ee/e2eeType";
-import { platform } from "./Platform";
+import {
+  BackgroundStyle,
+  configurationForIntent,
+  HeaderStyle,
+  type UrlConfiguration,
+  UserIntent,
+} from "./UrlConfiguration";
 import { redact } from "./utils/redact";
 
+// Moved to their own module, so that a host can import them without the rest
+// of this one; re-exported here as they always were
+export {
+  BackgroundStyle,
+  configurationForIntent,
+  HeaderStyle,
+  type UrlConfiguration,
+  UserIntent,
+} from "./UrlConfiguration";
+
 interface RoomIdentifier {
   roomAlias: string | null;
   roomId: string | null;
   viaServers: string[];
 }
 
-export enum UserIntent {
-  StartNewCall = "start_call",
-  JoinExistingCall = "join_existing",
-  StartNewCallVoice = "start_call_voice",
-  JoinExistingCallVoice = "join_existing_voice",
-  StartNewCallDM = "start_call_dm",
-  StartNewCallDMVoice = "start_call_dm_voice",
-  JoinExistingCallDM = "join_existing_dm",
-  JoinExistingCallDMVoice = "join_existing_dm_voice",
-  Unknown = "unknown",
-}
-
-export enum HeaderStyle {
-  None = "none",
-  Standard = "standard",
-  AppBar = "app_bar",
-}
-
-export enum BackgroundStyle {
-  Solid = "solid",
-  Gradient = "gradient",
-}
-
 /**
  * The UrlProperties are used to pass required data to the widget.
  * Those are different in different rooms, users, devices. They do not configure the behavior of the
@@ -166,109 +155,6 @@ export interface UrlProperties {
    */
   background: BackgroundStyle;
 }
-
-/**
- * The configuration for the app, which can be set via URL parameters.
- * Those property are different to the UrlProperties, since they are all optional
- * and configure the behavior of the app. Their value is the same if EC is used in
- * the same context but with different accounts/users.
- *
- * Their defaults can be controlled by the `intent` property.
- */
-export interface UrlConfiguration {
-  /**
-   * Whether the app should keep the user confined to the current call/room.
-   */
-  confineToRoom: boolean;
-  /**
-   * Whether the app should pause before joining the call until it sees an
-   * io.element.join widget action, allowing it to be preloaded.
-   */
-  preload: boolean;
-  /**
-   * The style of headers to show. "standard" is the default arrangement, "none"
-   * hides the header entirely, and "app_bar" produces a header with a back
-   * button like you might see in mobile apps. The callback for the back button
-   * is window.controls.onBackButtonPressed.
-   */
-  header: HeaderStyle;
-  /**
-   * Whether the controls should be shown. For screen recording no controls can be desired.
-   */
-  showControls: boolean;
-  /**
-   * Whether to hide the screen-sharing button.
-   */
-  hideScreensharing: boolean;
-
-  /**
-   * Whether the app is allowed to use fallback STUN servers for ICE in case the
-   * user's homeserver doesn't provide any.
-   */
-  allowIceFallback: boolean;
-
-  /**
-   * Whether the app should use per participant keys for E2EE.
-   */
-  perParticipantE2EE: boolean;
-  /**
-   * Whether the global JS controls for audio output devices should be enabled,
-   * allowing the list of output devices to be controlled by the app hosting
-   * Element Call.
-   */
-  controlledAudioDevices: boolean;
-  /**
-   * Setting this flag skips the lobby and brings you in the call directly.
-   * In the widget this can be combined with preload to pass the device settings
-   * with the join widget action.
-   */
-  skipLobby: boolean;
-  /**
-   * Setting this flag makes element call show the lobby after leaving a call.
-   * This is useful for video rooms.
-   */
-  returnToLobby: boolean;
-  /**
-   * Whether and what type of notification EC should send, when the user joins the call.
-   */
-  sendNotificationType?: RTCNotificationType;
-  /**
-   * Whether the app should automatically leave the call when there
-   * is no one left in the call.
-   * This is one part to make the call matrixRTC session behave like a telephone call.
-   */
-  autoLeaveWhenOthersLeft: boolean;
-
-  /**
-   * If the client should behave like it is awaiting an answer if a notification was sent (wait for call pick up).
-   * This is a no-op if not combined with sendNotificationType.
-   *
-   * This entails:
-   *  - show ui that it is awaiting an answer
-   *  - play a sound that indicates that it is awaiting an answer
-   *  - auto-dismiss the call widget once the notification lifetime expires on the receivers side.
-   */
-  waitForCallPickup: boolean;
-
-  /**
-   * Whether to enable echo cancellation for audio capture.
-   * Defaults to true.
-   */
-  echoCancellation?: boolean;
-  /**
-   * Whether to enable noise suppression for audio capture.
-   * Defaults to true.
-   */
-  noiseSuppression?: boolean;
-
-  callIntent?: RTCCallIntent;
-}
-
-// If you need to add a new flag to this interface, prefer a name that describes
-// a specific behavior (such as 'confineToRoom'), rather than one that describes
-// the situations that call for this behavior ('isEmbedded'). This makes it
-// clearer what each flag means, and helps us avoid coupling Element Call's
-// behavior to the needs of specific consumers.
 export interface UrlParams extends UrlProperties, UrlConfiguration {}
 
 class ParamParser {
@@ -354,97 +240,6 @@ export const getUrlParams = (
   return params;
 };
 
-/**
- * The configuration implied by what the user meant to do — if they pressed a
- * Start Call button this would be `start_call`, and if they pressed Join Call,
- * `join_existing`.
- *
- * These are platform-specific defaults, so that a host can start a call by
- * saying what the user asked for rather than by setting every parameter itself,
- * and so that what each intent means is Element Call's decision, made in one
- * place. A host that wants something else states it alongside the intent.
- *
- * {@link UserIntent.Unknown} means no intent was stated, and gives the
- * standalone app's defaults: Element Call owns the whole page, so it offers the
- * way out of the room that a hosted call must not.
- */
-export function configurationForIntent(intent: UserIntent): UrlConfiguration {
-  // Only constants and `platform` here, so that this depends on nothing but
-  // the intent.
-  let preset: UrlConfiguration = {
-    confineToRoom: true,
-    preload: false,
-    header: platform === "desktop" ? HeaderStyle.None : HeaderStyle.AppBar,
-    showControls: true,
-    hideScreensharing: false,
-    allowIceFallback: true,
-    perParticipantE2EE: true,
-    controlledAudioDevices: platform === "desktop" ? false : true,
-    skipLobby: true,
-    returnToLobby: false,
-    sendNotificationType: "notification",
-    autoLeaveWhenOthersLeft: false,
-    waitForCallPickup: false,
-  };
-  switch (intent) {
-    case UserIntent.StartNewCall:
-      preset.skipLobby = false;
-      preset.callIntent = "video";
-      break;
-    case UserIntent.JoinExistingCall:
-      // On desktop this will be overridden based on which button was used to join the call
-      preset.skipLobby = false;
-      preset.callIntent = "video";
-      break;
-    case UserIntent.StartNewCallVoice:
-      preset.skipLobby = false;
-      preset.callIntent = "audio";
-      break;
-    case UserIntent.JoinExistingCallVoice:
-      // On desktop this will be overridden based on which button was used to join the call
-      preset.skipLobby = false;
-      preset.callIntent = "audio";
-      break;
-    case UserIntent.StartNewCallDMVoice:
-      preset.callIntent = "audio";
-    // Fall through
-    case UserIntent.StartNewCallDM:
-      preset.skipLobby = true;
-      preset.sendNotificationType = "ring";
-      preset.autoLeaveWhenOthersLeft = true;
-      preset.waitForCallPickup = true;
-      preset.callIntent = preset.callIntent ?? "video";
-      break;
-    case UserIntent.JoinExistingCallDMVoice:
-      preset.callIntent = "audio";
-    // Fall through
-    case UserIntent.JoinExistingCallDM:
-      // On desktop this will be overridden based on which button was used to join the call
-      preset.skipLobby = true;
-      preset.autoLeaveWhenOthersLeft = true;
-      preset.callIntent = preset.callIntent ?? "video";
-      break;
-    // Non widget usecase defaults
-    default:
-      preset = {
-        confineToRoom: false,
-        preload: false,
-        header: HeaderStyle.Standard,
-        showControls: true,
-        hideScreensharing: false,
-        allowIceFallback: false,
-        perParticipantE2EE: false,
-        controlledAudioDevices: false,
-        skipLobby: false,
-        returnToLobby: false,
-        sendNotificationType: undefined,
-        autoLeaveWhenOthersLeft: false,
-        waitForCallPickup: false,
-      };
-  }
-  return preset;
-}
-
 /**
  * The {@link UrlProperties} for Element Call running as a component inside a
  * host application.

src/button/__snapshots__/ReactionToggleButton.test.tsx.snap

@@ -9,7 +9,7 @@ exports[`Can close reaction dialog 1`] = `
     aria-disabled="false"
     aria-expanded="true"
     aria-haspopup="true"
-    aria-labelledby="_r_bh_"
+    aria-labelledby="_r_bb_"
     class="_button_1nw83_8 _has-icon_1nw83_60 _icon-only_1nw83_53"
     data-kind="primary"
     data-size="lg"

src/reactions/index.ts

@@ -29,8 +29,6 @@ import waveSoundOgg from "../sound/reactions/wave.ogg?url";
 import waveSoundMp3 from "../sound/reactions/wave.mp3?url";
 import baduntssSoundOgg from "../sound/reactions/baduntss.ogg?url";
 import baduntssSoundMp3 from "../sound/reactions/baduntss.mp3?url";
-import bellSoundOgg from "../sound/reactions/bell.ogg?url";
-import bellSoundMp3 from "../sound/reactions/bell.mp3?url";
 
 export const ElementCallReactionEventType = "io.element.call.reaction";
 
@@ -204,15 +202,6 @@ export const ReactionSet: ReactionOption[] = [
       mp3: baduntssSoundMp3,
     },
   },
-  {
-    emoji: "🛎️",
-    name: "bell",
-    alias: ["ding"],
-    sound: {
-      ogg: bellSoundOgg,
-      mp3: bellSoundMp3,
-    },
-  },
 ];
 
 export interface RaisedHandInfo {

src/sound/LICENCE.md

@@ -10,7 +10,6 @@ The following sound effects have been licensed from Pixabay, under https://pixab
 - `reactions/generic`
 - `reactions/lightbulb`
 - `reactions/party`
-- `reactions/bell`
 
 ### Other
 

src/state/CallViewModel/CallViewModel.ts

@@ -16,6 +16,7 @@ import {
 import { type Room as MatrixRoom } from "matrix-js-sdk";
 import {
   BehaviorSubject,
+  catchError,
   combineLatest,
   distinctUntilChanged,
   filter,
@@ -38,7 +39,6 @@ import {
   throttleTime,
   timer,
   takeUntil,
-  from,
 } from "rxjs";
 import { type Logger, logger as rootLogger } from "matrix-js-sdk/lib/logger";
 import {
@@ -112,7 +112,7 @@ import {
   TransportState,
 } from "./localMember/LocalMember.ts";
 import {
-  getLocalTransport,
+  createLocalTransport$,
   type LocalTransport,
 } from "./localMember/LocalTransport.ts";
 import {
@@ -563,26 +563,20 @@ export function createCallViewModel$(
   const ownMembershipIdentity: CallMembershipIdentityParts = {
     userId,
     deviceId,
-    // Consumed by the sticky membership manager as `member.id`, *and* stamped
-    // into every to-device key event by the key transport. A pre-sticky
-    // membership advertises `${userId}:${deviceId}` as its `membershipID`
-    // instead, so a uuid there names a member no peer can resolve.
-    memberId:
-      matrixRTCMode === MatrixRTCMode.Matrix_2_0
-        ? uuidv4()
-        : `${userId}:${deviceId}`,
+    // This will only be consumed by the sticky membership manager. So it has no impact on legacy calls.
+    memberId: uuidv4(),
   };
 
-  const localTransport$ = options.localTransport
-    ? constant(options.localTransport)
-    : from(
-        getLocalTransport({
-          ownMembershipIdentity,
-          client,
-          roomId: matrixRoom.roomId,
-          matrixRTCMode,
-        }),
-      );
+  const localTransport =
+    options.localTransport ??
+    createLocalTransport$({
+      scope: scope,
+      memberships$: memberships$,
+      ownMembershipIdentity,
+      client,
+      roomId: matrixRoom.roomId,
+      matrixRTCMode,
+    });
 
   const connectionFactory =
     options.connectionFactory ??
@@ -599,7 +593,17 @@ export function createCallViewModel$(
   const connectionManager = createConnectionManager$({
     scope: scope,
     connectionFactory: connectionFactory,
-    localTransport$,
+    localTransport$: scope.behavior(
+      localTransport.active$.pipe(
+        catchError((e: unknown) => {
+          logger.info(
+            "could not pass local transport to createConnectionManager$. localTransport$ threw an error",
+            e,
+          );
+          return of(null);
+        }),
+      ),
+    ),
     remoteTransports$: membershipsAndTransports.transports$,
     logger: logger,
     ownMembershipIdentity,
@@ -655,7 +659,7 @@ export function createCallViewModel$(
     connectionManager,
     client,
     matrixRTCSession,
-    localTransport$,
+    localTransport,
     roomId: matrixRoom.roomId,
     hideScreensharing,
     hostBridge,

src/state/CallViewModel/CallViewModelTestUtils.ts

@@ -210,8 +210,11 @@ export function withCallViewModel(mode: MatrixRTCMode) {
         connectionState$,
         windowSize$,
         localTransport: {
-          transport: exampleTransport,
-          sfuConfig: exampleSfuConfig,
+          active$: constant({
+            transport: exampleTransport,
+            sfuConfig: exampleSfuConfig,
+          }),
+          advertised$: constant(exampleTransport),
         },
         connectionFactory: {
           createConnection(

src/state/CallViewModel/localMember/LocalMember.test.ts

@@ -21,7 +21,7 @@ import {
   beforeEach,
   afterEach,
 } from "vitest";
-import { BehaviorSubject, map, of, Subject } from "rxjs";
+import { BehaviorSubject, map, of } from "rxjs";
 import { logger } from "matrix-js-sdk/lib/logger";
 import { type LocalParticipant, type LocalTrack } from "livekit-client";
 import fetchMock from "fetch-mock";
@@ -50,7 +50,10 @@ import {
   TrackState,
   watchScreenShareToggle,
 } from "./LocalMember";
-import { MatrixRTCTransportMissingError } from "../../../utils/errors";
+import {
+  FailToGetOpenIdToken,
+  MatrixRTCTransportMissingError,
+} from "../../../utils/errors";
 import { Epoch, ObservableScope } from "../../ObservableScope";
 import { constant } from "../../Behavior";
 import { ConnectionManagerData } from "../remoteMembers/ConnectionManager";
@@ -58,7 +61,10 @@ import { ConnectionState, type Connection } from "../remoteMembers/Connection";
 import { type Publisher } from "./Publisher";
 import { initializeWidget } from "../../../widget";
 import { nullHostBridge } from "../../../HostBridge";
-import { type LocalTransport } from "./LocalTransport";
+import {
+  type LocalTransport,
+  type LocalTransportWithSFUConfig,
+} from "./LocalTransport";
 import * as openIDSFU from "../../../livekit/openIDSFU";
 
 initializeWidget();
@@ -255,7 +261,7 @@ describe("LocalMembership", () => {
   });
 
   it("throws error on missing RTC config error", () => {
-    withTestScheduler(({ scope, hot, expectObservable }) => {
+    withTestScheduler(({ scope, hot, behavior, expectObservable }) => {
       const localTransport$ = scope.behavior<null | LivekitTransportConfig>(
         hot("1ms #", {}, new MatrixRTCTransportMissingError("domain.com")),
         null,
@@ -271,15 +277,16 @@ describe("LocalMembership", () => {
         ),
       };
 
+      const aLocalTransport: LocalTransport = {
+        advertised$: localTransport$,
+        active$: behavior("a", { a: null }),
+      };
+
       const localMembership = createLocalMembership$({
         scope,
         ...defaultCreateLocalMemberValues,
         connectionManager: mockConnectionManager,
-        localTransport$: hot(
-          "1ms #",
-          {},
-          new MatrixRTCTransportMissingError("domain.com"),
-        ),
+        localTransport: aLocalTransport,
       });
 
       expectObservable(localMembership.localMemberState$).toBe("ne", {
@@ -289,9 +296,61 @@ describe("LocalMembership", () => {
     });
   });
 
+  it("Should not publish to active transport if advertised has errors", () => {
+    withTestScheduler(({ scope, hot, behavior, expectObservable }) => {
+      const advertised$ = scope.behavior<null | LivekitTransportConfig>(
+        hot("--#", {}, new FailToGetOpenIdToken(new Error("foo"))),
+        null,
+      );
+
+      // Populate a connection for active
+      const connectionManagerData = new ConnectionManagerData();
+      connectionManagerData.add(connectionTransportBConnected, []);
+      const mockConnectionManager = {
+        transports$: constant(new Epoch([bTransport])),
+        connectionManagerData$: constant(new Epoch(connectionManagerData)),
+      };
+
+      const aLocalTransport: LocalTransport = {
+        advertised$,
+        active$: behavior("a", { n: null, a: bTransportWithSFUConfig }),
+      };
+
+      defaultCreateLocalMemberValues.createPublisherFactory.mockImplementation(
+        () => {
+          return {} as unknown as Publisher;
+        },
+      );
+      const publisherFactory =
+        defaultCreateLocalMemberValues.createPublisherFactory as ReturnType<
+          typeof vi.fn
+        >;
+
+      const localMembership = createLocalMembership$({
+        scope,
+        ...defaultCreateLocalMemberValues,
+        connectionManager: mockConnectionManager,
+        localTransport: aLocalTransport,
+      });
+
+      expectObservable(localMembership.localMemberState$).toBe("n-e", {
+        n: TransportState.Waiting,
+        e: expect.toSatisfy((e) => e instanceof FailToGetOpenIdToken),
+      });
+
+      // Should not have created any publisher
+      expect(publisherFactory).toHaveBeenCalledTimes(0);
+    });
+  });
+
   it("logs if callIntent cannot be updated", async () => {
     const scope = new ObservableScope();
 
+    const aLocalTransport: LocalTransport = {
+      advertised$: constant(aTransport),
+      active$: constant(aTransportWithSFUConfig),
+    };
+
     const mockConnectionManager = {
       transports$: constant(new Epoch([])),
       connectionManagerData$: constant(new Epoch(new ConnectionManagerData())),
@@ -307,7 +366,7 @@ describe("LocalMembership", () => {
         leaveRoomSession: vi.fn(),
       },
       connectionManager: mockConnectionManager,
-      localTransport$: constant(mockTransport),
+      localTransport: aLocalTransport,
     });
     const expextedLog =
       "'not connected yet' while updating the call intent (this is expected on startup)";
@@ -319,19 +378,33 @@ describe("LocalMembership", () => {
     scope.end();
   });
 
-  const mockTransportConfig = {
+  const aTransport = {
     livekit_service_url: "a",
   } as LivekitTransportConfig;
 
-  const mockTransport = {
-    transport: mockTransportConfig,
+  const aTransportWithSFUConfig = {
+    transport: aTransport,
     sfuConfig: {
       jwt: "foo",
       livekitAlias: "bar",
       livekitIdentity: "baz",
       url: "bro",
     },
-  } as LocalTransport;
+  } as LocalTransportWithSFUConfig;
+
+  const bTransport = {
+    livekit_service_url: "b",
+  } as LivekitTransportConfig;
+
+  const bTransportWithSFUConfig = {
+    transport: bTransport,
+    sfuConfig: {
+      jwt: "foo2",
+      livekitAlias: "bar2",
+      livekitIdentity: "baz2",
+      url: "bro2",
+    },
+  } as LocalTransportWithSFUConfig;
 
   const connectionTransportAConnected = {
     livekitRoom: mockLivekitRoom({
@@ -341,13 +414,18 @@ describe("LocalMembership", () => {
       } as unknown as LocalParticipant,
     }),
     state$: constant(ConnectionState.LivekitConnected),
-    transport: mockTransportConfig,
-  } as Connection;
+    transport: aTransport,
+  } as unknown as Connection;
   const connectionTransportAConnecting = {
     ...connectionTransportAConnected,
     state$: constant(ConnectionState.LivekitConnecting),
     livekitRoom: mockLivekitRoom({}),
   } as unknown as Connection;
+  const connectionTransportBConnected = {
+    state$: constant(ConnectionState.LivekitConnected),
+    transport: bTransport,
+    livekitRoom: mockLivekitRoom({}),
+  } as unknown as Connection;
 
   const authCallSpy = vi
     .spyOn(openIDSFU, "getSFUConfigWithOpenID")
@@ -381,7 +459,10 @@ describe("LocalMembership", () => {
           ),
         },
         joinMatrixRTC,
-        localTransport$: constant(mockTransport),
+        localTransport: {
+          advertised$: constant(aTransport),
+          active$: constant(aTransportWithSFUConfig),
+        },
         delayId$,
       });
 
@@ -390,7 +471,7 @@ describe("LocalMembership", () => {
       await flushPromises();
       // Joins with timings appropriate for the level of delegation support
       expect(joinMatrixRTC).toHaveBeenCalledWith(
-        mockTransportConfig,
+        aTransport,
         delayedLeaveTimings,
       );
 
@@ -424,7 +505,75 @@ describe("LocalMembership", () => {
     },
   );
 
-  it("only starts tracks if requested", async () => {
+  it("recreates publisher if new connection is used, always unpublish and end tracks", async () => {
+    const scope = new ObservableScope();
+
+    const activeTransport$ = new BehaviorSubject(aTransportWithSFUConfig);
+    const aLocalTransport: LocalTransport = {
+      advertised$: constant(aTransport),
+      active$: activeTransport$,
+    };
+
+    const publishers: Publisher[] = [];
+    let seed = 0;
+    defaultCreateLocalMemberValues.createPublisherFactory.mockImplementation(
+      () => {
+        const a = seed;
+        seed += 1;
+        logger.info(`creating [${a}]`);
+        const p = {
+          // It is enought to check if destroy is called. Destroy itself is tested in the publisher to make sure it does
+          // all the cleanup we need.
+          destroy: vi.fn(),
+          stopPublishing: vi.fn().mockImplementation(() => {
+            logger.info(`stopPublishing [${a}]`);
+          }),
+          stopTracks: vi.fn(),
+        };
+        publishers.push(p as unknown as Publisher);
+        return p;
+      },
+    );
+    const publisherFactory =
+      defaultCreateLocalMemberValues.createPublisherFactory as ReturnType<
+        typeof vi.fn
+      >;
+
+    const connectionManagerData = new ConnectionManagerData();
+    connectionManagerData.add(connectionTransportAConnected, []);
+    connectionManagerData.add(connectionTransportBConnected, []);
+    createLocalMembership$({
+      scope,
+      ...defaultCreateLocalMemberValues,
+      connectionManager: {
+        connectionManagerData$: constant(new Epoch(connectionManagerData)),
+      },
+      localTransport: aLocalTransport,
+    });
+    await flushPromises();
+    activeTransport$.next({
+      ...aTransportWithSFUConfig,
+      transport: bTransport,
+    });
+    await flushPromises();
+
+    expect(publisherFactory).toHaveBeenCalledTimes(2);
+    expect(publishers.length).toBe(2);
+    // stop the first Publisher and let the second one life.
+    expect(publishers[0].destroy).toHaveBeenCalled();
+    expect(publishers[1].destroy).not.toHaveBeenCalled();
+    expect(publisherFactory.mock.calls[0][0].transport).toBe(aTransport);
+    expect(publisherFactory.mock.calls[1][0].transport).toBe(bTransport);
+    scope.end();
+    await flushPromises();
+    // stop all tracks after ending scopes
+    expect(publishers[1].destroy).toHaveBeenCalled();
+    // expect(publishers[1].stopTracks).toHaveBeenCalled();
+
+    defaultCreateLocalMemberValues.createPublisherFactory.mockReset();
+  });
+
+  it("only start tracks if requested", async () => {
     const scope = new ObservableScope();
 
     const publishers: Publisher[] = [];
@@ -453,6 +602,11 @@ describe("LocalMembership", () => {
         typeof vi.fn
       >;
 
+    const aLocalTransport: LocalTransport = {
+      advertised$: constant(aTransport),
+      active$: constant(aTransportWithSFUConfig),
+    };
+
     const connectionManagerData = new ConnectionManagerData();
     connectionManagerData.add(connectionTransportAConnected, []);
     // connectionManagerData.add(connectionTransportB, []);
@@ -462,7 +616,7 @@ describe("LocalMembership", () => {
       connectionManager: {
         connectionManagerData$: constant(new Epoch(connectionManagerData)),
       },
-      localTransport$: constant(mockTransport),
+      localTransport: aLocalTransport,
     });
     await flushPromises();
     expect(publisherFactory).toHaveBeenCalledOnce();
@@ -483,8 +637,16 @@ describe("LocalMembership", () => {
   //
   it("tracks livekit state correctly", async () => {
     const scope = new ObservableScope();
+
     const connectionManagerData = new ConnectionManagerData();
-    const localTransport$ = new Subject<LocalTransport>();
+
+    const activeTransport$ =
+      new BehaviorSubject<null | LocalTransportWithSFUConfig>(null);
+
+    const aLocalTransport: LocalTransport = {
+      advertised$: constant(aTransport),
+      active$: activeTransport$,
+    };
 
     const connectionManagerData$ = new BehaviorSubject(
       new Epoch(connectionManagerData),
@@ -525,14 +687,14 @@ describe("LocalMembership", () => {
       connectionManager: {
         connectionManagerData$,
       },
-      localTransport$,
+      localTransport: aLocalTransport,
     });
 
     await flushPromises();
     expect(localMembership.localMemberState$.value).toStrictEqual(
       TransportState.Waiting,
     );
-    localTransport$.next(mockTransport);
+    activeTransport$.next(aTransportWithSFUConfig);
     await flushPromises();
     expect(localMembership.localMemberState$.value).toStrictEqual({
       matrix: RTCMemberStatus.Connected,
@@ -557,7 +719,7 @@ describe("LocalMembership", () => {
     });
 
     (
-      connectionManagerData2.getConnectionForTransport(mockTransportConfig)!
+      connectionManagerData2.getConnectionForTransport(aTransport)!
         .state$ as BehaviorSubject<ConnectionState>
     ).next(ConnectionState.LivekitConnected);
     expect(localMembership.localMemberState$.value).toStrictEqual({
@@ -660,7 +822,10 @@ describe("LocalMembership", () => {
         connectionManager: {
           connectionManagerData$: constant(new Epoch(connectionManagerData)),
         },
-        localTransport$: constant(mockTransport),
+        localTransport: {
+          advertised$: constant(aTransport),
+          active$: constant(aTransportWithSFUConfig),
+        },
       });
 
       await flushPromises();
@@ -697,7 +862,10 @@ describe("LocalMembership", () => {
         connectionManager: {
           connectionManagerData$: constant(new Epoch(connectionManagerData)),
         },
-        localTransport$: constant(mockTransport),
+        localTransport: {
+          advertised$: constant(aTransport),
+          active$: constant(aTransportWithSFUConfig),
+        },
       });
 
       await flushPromises();
@@ -745,7 +913,10 @@ describe("LocalMembership", () => {
         connectionManager: {
           connectionManagerData$: constant(new Epoch(connectionManagerData)),
         },
-        localTransport$: constant(mockTransport),
+        localTransport: {
+          advertised$: constant(aTransport),
+          active$: constant(aTransportWithSFUConfig),
+        },
       });
 
       await flushPromises();
@@ -786,7 +957,10 @@ describe("LocalMembership", () => {
         connectionManager: {
           connectionManagerData$: constant(new Epoch(connectionManagerData)),
         },
-        localTransport$: constant(mockTransport),
+        localTransport: {
+          advertised$: constant(aTransport),
+          active$: constant(aTransportWithSFUConfig),
+        },
       });
 
       await flushPromises();
@@ -852,7 +1026,10 @@ describe("LocalMembership", () => {
         connectionManager: {
           connectionManagerData$: constant(new Epoch(connectionManagerData)),
         },
-        localTransport$: constant(mockTransport),
+        localTransport: {
+          advertised$: constant(aTransport),
+          active$: constant(aTransportWithSFUConfig),
+        },
       });
       return { scope, localMembership };
     };
@@ -862,7 +1039,7 @@ describe("LocalMembership", () => {
       const setScreenShareEnabled = vi.fn().mockRejectedValue(error);
       const connection = {
         state$: constant(ConnectionState.LivekitConnected),
-        transport: mockTransportConfig,
+        transport: aTransport,
         livekitRoom: mockLivekitRoom({
           localParticipant: mockLocalParticipant({
             isScreenShareEnabled: false,

src/state/CallViewModel/localMember/LocalMember.ts

@@ -38,10 +38,6 @@ import {
   startWith,
   switchMap,
   tap,
-  NEVER,
-  concat,
-  race,
-  Subject,
 } from "rxjs";
 import { type Logger } from "matrix-js-sdk/lib/logger";
 import { deepCompare } from "matrix-js-sdk/lib/utils";
@@ -81,6 +77,8 @@ import {
 } from "../remoteMembers/Connection.ts";
 import { type HomeserverConnected } from "./HomeserverConnected.ts";
 import { type LocalTransport } from "./LocalTransport.ts";
+import { areLivekitTransportsEqual } from "../remoteMembers/MatrixLivekitMembers.ts";
+import { or$ } from "../../../utils/observable.ts";
 import { getSFUConfigWithOpenID } from "../../../livekit/openIDSFU.ts";
 
 export enum TransportState {
@@ -150,7 +148,7 @@ interface Props {
   homeserverConnected: HomeserverConnected;
   roomId: string;
   ownMembershipIdentity: CallMembershipIdentityParts;
-  localTransport$: Observable<LocalTransport>;
+  localTransport: LocalTransport;
   client: Pick<MatrixClient, "getDeviceId" | "getOpenIdToken">;
   matrixRTCSession: Pick<
     MatrixRTCSession,
@@ -196,7 +194,7 @@ interface Props {
 export const createLocalMembership$ = ({
   scope,
   connectionManager,
-  localTransport$: localTransportWithErrors$,
+  localTransport,
   homeserverConnected,
   createPublisherFactory,
   joinMatrixRTC,
@@ -254,24 +252,20 @@ export const createLocalMembership$ = ({
   const logger = parentLogger.getChild("[LocalMembership]");
   logger.debug(`Creating local membership..`);
 
-  // Unwrap the local transport and set the state of the LocalMembership to error in case the transport is an error.
-  const fatalTransportError$ = new Subject<ElementCallError>();
-  const localTransport$ = localTransportWithErrors$.pipe(
-    catchError((e: unknown) => {
-      let error: ElementCallError;
-      if (e instanceof ElementCallError) {
-        error = e;
-      } else {
-        error = new UnknownCallError(
-          e instanceof Error
-            ? e
-            : new Error("Unknown error from localTransport"),
-        );
-      }
-      fatalTransportError$.next(error);
-      return NEVER; // Make this Observable swallow the error
-    }),
-  );
+  // We consider error on the transport as fatal.
+  // Whether it is the active transport or the preferred transport.
+  const handleTransportError = (e: unknown): Observable<null> => {
+    let error: ElementCallError;
+    if (e instanceof ElementCallError) {
+      error = e;
+    } else {
+      error = new UnknownCallError(
+        e instanceof Error ? e : new Error("Unknown error from localTransport"),
+      );
+    }
+    setTransportError(error);
+    return of(null);
+  };
 
   async function checkDelegationSupport(
     endpointUrl: string,
@@ -309,40 +303,58 @@ export const createLocalMembership$ = ({
 
   // The transport that we will advertise in our membership, paired with info as
   // to whether delayed event delegation is supported
-  const joinParams$ = scope.behavior(
-    localTransport$.pipe(
-      switchMap(async ({ transport }) => {
-        const transportSupportsDelegation = checkDelegationSupport(
-          transport.livekit_service_url + "/delegate_delayed_leave",
-          `transport ${transport.livekit_service_url}`,
-        );
-        return {
-          transport,
-          delegationSupported:
-            (await homeserverSupportsDelegation) ||
-            (await transportSupportsDelegation),
-        };
+  const joinParams$ = localTransport.advertised$.pipe(
+    catchError(handleTransportError),
+    distinctUntilChanged(areLivekitTransportsEqual),
+    switchMap((transport) => {
+      if (transport === null) return of(null);
+      const transportSupportsDelegation = checkDelegationSupport(
+        transport.livekit_service_url + "/delegate_delayed_leave",
+        `transport ${transport.livekit_service_url}`,
+      );
+      return or$(
+        from(homeserverSupportsDelegation),
+        from(transportSupportsDelegation),
+      ).pipe(
+        map((delegationSupported) => ({ transport, delegationSupported })),
+        startWith(null),
+      );
+    }),
+  );
+
+  // Unwrap the local transport and set the state of the LocalMembership to error in case the transport is an error.
+  const activeTransport$ = scope.behavior(
+    combineLatest([localTransport.active$, localTransport.advertised$]).pipe(
+      map(([active, advertised]) => {
+        // Our policy is to not publish to another transport if our prefered transport is miss-configured
+        if (advertised == null) return null;
+
+        return active?.transport ?? null;
       }),
+      catchError(handleTransportError),
+      distinctUntilChanged(areLivekitTransportsEqual),
     ),
-    null,
   );
 
   // Drop Epoch data here since we will not combine this anymore
   const localConnection$ = scope.behavior(
     combineLatest([
       connectionManager.connectionManagerData$,
-      localTransport$,
+      activeTransport$,
     ]).pipe(
-      map(([{ value: connectionData }, { transport }]) =>
-        connectionData.getConnectionForTransport(transport),
-      ),
+      map(([{ value: connectionData }, localTransport]) => {
+        if (localTransport === null) {
+          return null;
+        }
+
+        return connectionData.getConnectionForTransport(localTransport);
+      }),
       tap((connection) => {
         logger.info(
           `Local connection updated: ${connection?.transport?.livekit_service_url}`,
         );
       }),
     ),
-    null,
   );
 
   // Tracks error that happen when creating the local tracks.
@@ -478,6 +490,18 @@ export const createLocalMembership$ = ({
     }
   };
 
+  const fatalTransportError$ = new BehaviorSubject<ElementCallError | null>(
+    null,
+  );
+
+  const setTransportError = (e: ElementCallError): void => {
+    if (fatalTransportError$.value !== null) {
+      logger.error("Multiple Transport Errors:", e);
+    } else {
+      fatalTransportError$.next(e);
+    }
+  };
+
   const localConnectionState$ = localConnection$.pipe(
     switchMap((connection) => (connection ? connection.state$ : of(null))),
   );
@@ -485,29 +509,38 @@ export const createLocalMembership$ = ({
   const mediaState$: Behavior<LocalMemberMediaState> = scope.behavior(
     combineLatest([
       localConnectionState$,
+      activeTransport$,
       joinAndPublishRequested$,
       from(trackStartRequested.promise).pipe(
         map(() => true),
         startWith(false),
       ),
     ]).pipe(
-      map(([localConnectionState, shouldPublish, shouldStartTracks]) => {
-        const trackState: TrackState = shouldStartTracks
-          ? TrackState.Ready
-          : TrackState.WaitingForUser;
+      map(
+        ([
+          localConnectionState,
+          localTransport,
+          shouldPublish,
+          shouldStartTracks,
+        ]) => {
+          if (!localTransport) return null;
+          const trackState: TrackState = shouldStartTracks
+            ? TrackState.Ready
+            : TrackState.WaitingForUser;
 
-        if (
-          localConnectionState !== ConnectionState.LivekitConnected ||
-          trackState !== TrackState.Ready
-        )
-          return {
-            connection: localConnectionState,
-            tracks: trackState,
-          };
-        if (!shouldPublish) return PublishState.WaitingForUser;
-        // if (!publishing) return PublishState.Starting;
-        return PublishState.Publishing;
-      }),
+          if (
+            localConnectionState !== ConnectionState.LivekitConnected ||
+            trackState !== TrackState.Ready
+          )
+            return {
+              connection: localConnectionState,
+              tracks: trackState,
+            };
+          if (!shouldPublish) return PublishState.WaitingForUser;
+          // if (!publishing) return PublishState.Starting;
+          return PublishState.Publishing;
+        },
+      ),
       distinctUntilChanged(deepCompare),
     ),
   );
@@ -521,36 +554,30 @@ export const createLocalMembership$ = ({
   };
 
   const localMemberState$ = scope.behavior<LocalMemberState>(
-    concat(
-      // Waiting until…
-      of(TransportState.Waiting),
-      race(
-        // either there is a fatal transport error
-        fatalTransportError$,
-        // or the transport is available.
-        localTransport$.pipe(
-          switchMap(() =>
-            // Once available, track session/media state.
-            combineLatest([
-              mediaState$,
-              homeserverConnected.rtsSession$,
-              fatalMatrixError$,
-              publishError$,
-            ]).pipe(
-              map(
-                ([
-                  mediaState,
-                  rtcSessionStatus,
-                  fatalMatrixError,
-                  publishError,
-                ]) => ({
-                  matrix: fatalMatrixError ?? rtcSessionStatus,
-                  media: publishError ?? mediaState,
-                }),
-              ),
-            ),
-          ),
-        ),
+    combineLatest([
+      mediaState$,
+      homeserverConnected.rtsSession$,
+      fatalMatrixError$,
+      fatalTransportError$,
+      publishError$,
+    ]).pipe(
+      map(
+        ([
+          mediaState,
+          rtcSessionStatus,
+          fatalMatrixError,
+          fatalTransportError,
+          publishError,
+        ]) => {
+          if (fatalTransportError !== null) return fatalTransportError;
+          // `mediaState` will be 'null' until the transport/connection appears.
+          if (mediaState && rtcSessionStatus)
+            return {
+              matrix: fatalMatrixError ?? rtcSessionStatus,
+              media: publishError ?? mediaState,
+            };
+          return TransportState.Waiting;
+        },
       ),
     ),
   );
@@ -658,7 +685,7 @@ export const createLocalMembership$ = ({
       });
   });
 
-  // Join and leave the session as needed
+  // Keep matrix rtc session in sync with advertisedTransport$, connectRequested$
   scope.reconcile(
     scope.behavior(combineLatest([joinParams$, joinAndPublishRequested$])),
     async ([joinParams, shouldConnect]) => {

src/state/CallViewModel/localMember/LocalTransport.test.ts

@@ -14,10 +14,19 @@ import {
   type MockedObject,
   vi,
 } from "vitest";
+import { type CallMembership } from "matrix-js-sdk/lib/matrixrtc";
+import { lastValueFrom } from "rxjs";
 import fetchMock from "fetch-mock";
 
-import { mockConfig, ownMemberMock } from "../../../utils/test";
-import { getLocalTransport } from "./LocalTransport";
+import {
+  mockConfig,
+  flushPromises,
+  ownMemberMock,
+  testScope,
+} from "../../../utils/test";
+import { createLocalTransport$ } from "./LocalTransport";
+import { constant } from "../../Behavior";
+import { Epoch, ObservableScope } from "../../ObservableScope";
 import {
   MatrixRTCTransportMissingError,
   FailToGetOpenIdToken,
@@ -38,79 +47,118 @@ describe("LocalTransport", () => {
   beforeEach(() => vi.clearAllMocks());
 
   it("throws if config is missing", async () => {
-    await expect(
-      getLocalTransport({
-        roomId: "!room:example.org",
-        client: {
-          // eslint-disable-next-line @typescript-eslint/naming-convention
-          _unstable_getRTCTransports: async () => Promise.resolve([]),
-          getDomain: () => "example.org",
-          // These won't be called in this error path but satisfy the type
-          getOpenIdToken: vi.fn(),
-          getDeviceId: vi.fn(),
-        },
-        ownMembershipIdentity: ownMemberMock,
-        matrixRTCMode: MatrixRTCMode.Compatibility,
-      }),
-    ).rejects.toThrow(new MatrixRTCTransportMissingError("example.org"));
+    const { advertised$, active$ } = createLocalTransport$({
+      scope: testScope(),
+      roomId: "!room:example.org",
+      memberships$: constant(new Epoch<CallMembership[]>([])),
+      client: {
+        // eslint-disable-next-line @typescript-eslint/naming-convention
+        _unstable_getRTCTransports: async () => Promise.resolve([]),
+        getDomain: () => "example.org",
+        // These won't be called in this error path but satisfy the type
+        getOpenIdToken: vi.fn(),
+        getDeviceId: vi.fn(),
+      },
+      ownMembershipIdentity: ownMemberMock,
+      matrixRTCMode: MatrixRTCMode.Compatibility,
+    });
+    await flushPromises();
+
+    expect(() => advertised$.value).toThrow(
+      new MatrixRTCTransportMissingError("example.org"),
+    );
+    expect(() => active$.value).toThrow(
+      new MatrixRTCTransportMissingError("example.org"),
+    );
   });
 
   it("throws FailToGetOpenIdToken when OpenID fetch fails", async () => {
     // Provide a valid config so makeTransportInternal resolves a transport
+    const scope = new ObservableScope();
     mockConfig({
       livekit: { livekit_service_url: "https://lk.example.org" },
     });
-    vi.spyOn(openIDSFU, "getSFUConfigWithOpenID").mockRejectedValue(
-      new FailToGetOpenIdToken(new Error("no openid")),
+    const resolver = Promise.withResolvers<void>();
+    vi.spyOn(openIDSFU, "getSFUConfigWithOpenID").mockImplementation(
+      async () => {
+        await resolver.promise;
+        throw new FailToGetOpenIdToken(new Error("no openid"));
+      },
     );
+    const observations: unknown[] = [];
+    const errors: Error[] = [];
+    const { advertised$, active$ } = createLocalTransport$({
+      scope,
+      roomId: "!example_room_id",
+      memberships$: constant(new Epoch<CallMembership[]>([])),
+      client: {
+        getDomain: () => "example.org",
+        // eslint-disable-next-line @typescript-eslint/naming-convention
+        _unstable_getRTCTransports: async () => Promise.resolve([]),
+        getOpenIdToken: vi.fn(),
+        getDeviceId: vi.fn(),
+      },
+      ownMembershipIdentity: ownMemberMock,
+      matrixRTCMode: MatrixRTCMode.Compatibility,
+    });
+    active$.subscribe(
+      (o) => observations.push(o),
+      (e) => errors.push(e),
+    );
+    resolver.resolve();
+    await flushPromises();
 
-    await expect(
-      getLocalTransport({
-        roomId: "!example_room_id",
-        client: {
-          getDomain: () => "example.org",
-          // eslint-disable-next-line @typescript-eslint/naming-convention
-          _unstable_getRTCTransports: async () => Promise.resolve([]),
-          getOpenIdToken: vi.fn(),
-          getDeviceId: vi.fn(),
-        },
-        ownMembershipIdentity: ownMemberMock,
-        matrixRTCMode: MatrixRTCMode.Compatibility,
-      }),
-    ).rejects.toThrow(new FailToGetOpenIdToken(new Error("no openid")));
+    const expectedError = new FailToGetOpenIdToken(new Error("no openid"));
+    expect(observations).toStrictEqual([null]);
+    expect(errors).toStrictEqual([expectedError]);
+    expect(() => advertised$.value).toThrow(expectedError);
+    expect(() => active$.value).toThrow(expectedError);
   });
 
-  it("returns preferred transport", async () => {
+  it("emits preferred transport after OpenID resolves", async () => {
     // Use config so transport discovery succeeds, but delay OpenID JWT fetch
     mockConfig({
       livekit: { livekit_service_url: "https://lk.example.org" },
     });
 
-    vi.spyOn(openIDSFU, "getSFUConfigWithOpenID").mockResolvedValue({
+    const openIdResolver = Promise.withResolvers<openIDSFU.SFUConfig>();
+
+    vi.spyOn(openIDSFU, "getSFUConfigWithOpenID").mockReturnValue(
+      openIdResolver.promise,
+    );
+
+    const { advertised$, active$ } = createLocalTransport$({
+      scope: testScope(),
+      roomId: "!room:example.org",
+      memberships$: constant(new Epoch<CallMembership[]>([])),
+      client: {
+        // eslint-disable-next-line @typescript-eslint/naming-convention
+        _unstable_getRTCTransports: async () => Promise.resolve([]),
+        getDomain: () => "example.org",
+        getOpenIdToken: vi.fn(),
+        getDeviceId: vi.fn(),
+      },
+      ownMembershipIdentity: ownMemberMock,
+      matrixRTCMode: MatrixRTCMode.Compatibility,
+    });
+
+    openIdResolver.resolve?.({
       url: "https://lk.example.org",
       jwt: "jwt",
       livekitAlias: "Akph4alDMhen",
       livekitIdentity: ownMemberMock.userId + ":" + ownMemberMock.deviceId,
     });
-
-    expect(
-      await getLocalTransport({
-        roomId: "!room:example.org",
-        client: {
-          // eslint-disable-next-line @typescript-eslint/naming-convention
-          _unstable_getRTCTransports: async () => Promise.resolve([]),
-          getDomain: () => "example.org",
-          getOpenIdToken: vi.fn(),
-          getDeviceId: vi.fn(),
-        },
-        ownMembershipIdentity: ownMemberMock,
-        matrixRTCMode: MatrixRTCMode.Compatibility,
-      }),
-    ).toStrictEqual({
-      transport: {
-        livekit_service_url: "https://lk.example.org",
-        type: "livekit",
-      },
+    expect(advertised$.value).toBe(null);
+    expect(active$.value).toBe(null);
+    await flushPromises();
+    // final
+    const expectedTransport = {
+      livekit_service_url: "https://lk.example.org",
+      type: "livekit",
+    };
+    expect(advertised$.value).toStrictEqual(expectedTransport);
+    expect(active$.value).toStrictEqual({
+      transport: expectedTransport,
       sfuConfig: {
         jwt: "jwt",
         livekitAlias: "Akph4alDMhen",
@@ -120,19 +168,22 @@ describe("LocalTransport", () => {
     });
   });
 
-  type LocalTransportProps = Parameters<typeof getLocalTransport>[0];
+  type LocalTransportProps = Parameters<typeof createLocalTransport$>[0];
 
   describe("transport configuration mechanisms", () => {
     let localTransportOpts: LocalTransportProps & {
       client: MockedObject<LocalTransportProps["client"]>;
     };
+    let openIdResolver: PromiseWithResolvers<openIDSFU.SFUConfig>;
     beforeEach(() => {
       mockConfig({});
       customLivekitUrl.setValue(customLivekitUrl.defaultValue);
       localTransportOpts = {
         ownMembershipIdentity: ownMemberMock,
+        scope: testScope(),
         roomId: "!example_room_id",
         matrixRTCMode: MatrixRTCMode.Compatibility,
+        memberships$: constant(new Epoch<CallMembership[]>([])),
         client: {
           getDomain: vi.fn().mockReturnValue("example.org"),
           // eslint-disable-next-line @typescript-eslint/naming-convention
@@ -141,6 +192,10 @@ describe("LocalTransport", () => {
           getDeviceId: vi.fn(),
         },
       };
+      openIdResolver = Promise.withResolvers<openIDSFU.SFUConfig>();
+      vi.spyOn(openIDSFU, "getSFUConfigWithOpenID").mockReturnValue(
+        openIdResolver.promise,
+      );
     });
 
     afterEach(() => {
@@ -151,15 +206,19 @@ describe("LocalTransport", () => {
       mockConfig({
         livekit: { livekit_service_url: "https://lk.example.org" },
       });
-      vi.spyOn(openIDSFU, "getSFUConfigWithOpenID").mockResolvedValue(
-        openIdResponse,
-      );
-
-      expect(await getLocalTransport(localTransportOpts)).toStrictEqual({
-        transport: {
-          livekit_service_url: "https://lk.example.org",
-          type: "livekit",
-        },
+      const { advertised$, active$ } =
+        createLocalTransport$(localTransportOpts);
+      openIdResolver.resolve?.(openIdResponse);
+      expect(advertised$.value).toBe(null);
+      expect(active$.value).toBe(null);
+      await flushPromises();
+      const expectedTransport = {
+        livekit_service_url: "https://lk.example.org",
+        type: "livekit",
+      };
+      expect(advertised$.value).toStrictEqual(expectedTransport);
+      expect(active$.value).toStrictEqual({
+        transport: expectedTransport,
         sfuConfig: {
           jwt: "e30=.eyJzdWIiOiJAbWU6ZXhhbXBsZS5vcmc6QUJDREVGIiwidmlkZW8iOnsicm9vbSI6IiFleGFtcGxlX3Jvb21faWQifX0=.e30=",
           livekitAlias: "Akph4alDMhen",
@@ -171,11 +230,12 @@ describe("LocalTransport", () => {
 
     it("supports getting transport via user settings", async () => {
       customLivekitUrl.setValue("https://lk.example.org");
-      vi.spyOn(openIDSFU, "getSFUConfigWithOpenID").mockResolvedValue(
-        openIdResponse,
-      );
-
-      expect(await getLocalTransport(localTransportOpts)).toStrictEqual({
+      const { advertised$, active$ } =
+        createLocalTransport$(localTransportOpts);
+      openIdResolver.resolve?.(openIdResponse);
+      expect(advertised$.value).toBe(null);
+      await flushPromises();
+      expect(active$.value).toStrictEqual({
         transport: {
           livekit_service_url: "https://lk.example.org",
           type: "livekit",
@@ -193,15 +253,19 @@ describe("LocalTransport", () => {
       localTransportOpts.client._unstable_getRTCTransports.mockResolvedValue([
         { type: "livekit", livekit_service_url: "https://lk.example.org" },
       ]);
-      vi.spyOn(openIDSFU, "getSFUConfigWithOpenID").mockResolvedValue(
-        openIdResponse,
-      );
-
-      expect(await getLocalTransport(localTransportOpts)).toStrictEqual({
-        transport: {
-          livekit_service_url: "https://lk.example.org",
-          type: "livekit",
-        },
+      const { advertised$, active$ } =
+        createLocalTransport$(localTransportOpts);
+      openIdResolver.resolve?.(openIdResponse);
+      expect(advertised$.value).toBe(null);
+      expect(active$.value).toBe(null);
+      await flushPromises();
+      const expectedTransport = {
+        livekit_service_url: "https://lk.example.org",
+        type: "livekit",
+      };
+      expect(advertised$.value).toStrictEqual(expectedTransport);
+      expect(active$.value).toStrictEqual({
+        transport: expectedTransport,
         sfuConfig: {
           jwt: "e30=.eyJzdWIiOiJAbWU6ZXhhbXBsZS5vcmc6QUJDREVGIiwidmlkZW8iOnsicm9vbSI6IiFleGFtcGxlX3Jvb21faWQifX0=.e30=",
           livekitAlias: "Akph4alDMhen",
@@ -215,31 +279,38 @@ describe("LocalTransport", () => {
       localTransportOpts.client._unstable_getRTCTransports.mockResolvedValue([
         { type: "livekit", livekit_service_url: "https://lk.example.org" },
       ]);
-      vi.spyOn(openIDSFU, "getSFUConfigWithOpenID").mockRejectedValue(
+      openIdResolver.reject(
         new FailToGetOpenIdToken(new Error("Test driven error")),
       );
-
-      await expect(getLocalTransport(localTransportOpts)).rejects.toThrow(
-        expect.any(FailToGetOpenIdToken),
-      );
+      await expect(async () =>
+        lastValueFrom(createLocalTransport$(localTransportOpts).active$),
+      ).rejects.toThrow(expect.any(FailToGetOpenIdToken));
     });
 
     it("throws if no options are available", async () => {
-      await expect(
-        getLocalTransport({
-          ownMembershipIdentity: ownMemberMock,
-          roomId: "!example_room_id",
-          matrixRTCMode: MatrixRTCMode.Compatibility,
-          client: {
-            getDomain: () => "example.org",
-            // eslint-disable-next-line @typescript-eslint/naming-convention
-            _unstable_getRTCTransports: async () => Promise.resolve([]),
-            // These won't be called in this error path but satisfy the type
-            getOpenIdToken: vi.fn(),
-            getDeviceId: vi.fn(),
-          },
-        }),
-      ).rejects.toThrow(new MatrixRTCTransportMissingError("example.org"));
+      const { advertised$, active$ } = createLocalTransport$({
+        scope: testScope(),
+        ownMembershipIdentity: ownMemberMock,
+        roomId: "!example_room_id",
+        matrixRTCMode: MatrixRTCMode.Compatibility,
+        memberships$: constant(new Epoch<CallMembership[]>([])),
+        client: {
+          getDomain: () => "example.org",
+          // eslint-disable-next-line @typescript-eslint/naming-convention
+          _unstable_getRTCTransports: async () => Promise.resolve([]),
+          // These won't be called in this error path but satisfy the type
+          getOpenIdToken: vi.fn(),
+          getDeviceId: vi.fn(),
+        },
+      });
+      await flushPromises();
+
+      expect(() => advertised$.value).toThrow(
+        new MatrixRTCTransportMissingError("example.org"),
+      );
+      expect(() => active$.value).toThrow(
+        new MatrixRTCTransportMissingError("example.org"),
+      );
     });
   });
 });

src/state/CallViewModel/localMember/LocalTransport.ts

@@ -5,11 +5,17 @@ SPDX-License-IdFentifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
-import { type LivekitTransportConfig } from "matrix-js-sdk/lib/matrixrtc";
+import {
+  type CallMembership,
+  type LivekitTransportConfig,
+} from "matrix-js-sdk/lib/matrixrtc";
 import { type MatrixClient } from "matrix-js-sdk";
+import { distinctUntilChanged, from, map, of, switchMap } from "rxjs";
 import { logger as rootLogger, type Logger } from "matrix-js-sdk/lib/logger";
 import { type CallMembershipIdentityParts } from "matrix-js-sdk/lib/matrixrtc/EncryptionManager";
 
+import { type Behavior } from "../../Behavior.ts";
+import { type Epoch, type ObservableScope } from "../../ObservableScope.ts";
 import { Config } from "../../../config/Config.ts";
 import {
   FailToGetOpenIdToken,
@@ -21,12 +27,19 @@ import {
   type SFUConfig,
   type OpenIDClientParts,
 } from "../../../livekit/openIDSFU.ts";
+import { areLivekitTransportsEqual } from "../remoteMembers/MatrixLivekitMembers.ts";
 import { customLivekitUrl } from "../../../settings/settings.ts";
 import { RtcTransportAutoDiscovery } from "./RtcTransportAutoDiscovery.ts";
 import { type MatrixRTCMode } from "../../../config/ConfigOptions.ts";
 
+/*
+ * It figures out “which LiveKit focus URL/alias the local user should use,”
+ * and ensures the SFU path is primed before advertising that choice.
+ */
 interface Props {
+  scope: ObservableScope;
   ownMembershipIdentity: CallMembershipIdentityParts;
+  memberships$: Behavior<Epoch<CallMembership[]>>;
   client: Pick<MatrixClient, "getDomain" | "_unstable_getRTCTransports"> &
     OpenIDClientParts;
   // Used by the jwt service to create the livekit room and compute the livekit alias.
@@ -55,65 +68,114 @@ interface Props {
 //
 // 2.
 // We need to make sure we do not sent livekit_alias in sticky events and that we drop all code for sending state events!
-export interface LocalTransport {
+export interface LocalTransportWithSFUConfig {
   transport: LivekitTransportConfig;
   sfuConfig: SFUConfig;
 }
 
-export function isLocalTransport(
-  obj: LivekitTransportConfig | LocalTransport,
-): obj is LocalTransport {
+export function isLocalTransportWithSFUConfig(
+  obj: LivekitTransportConfig | LocalTransportWithSFUConfig,
+): obj is LocalTransportWithSFUConfig {
   return "transport" in obj && "sfuConfig" in obj;
 }
 
+export interface LocalTransport {
+  /**
+   * The transport to be advertised in our MatrixRTC membership. `null` when not
+   * yet fetched/validated.
+   */
+  advertised$: Behavior<LivekitTransportConfig | null>;
+  /**
+   * The transport to connect to and publish media on. `null` when not yet known
+   * or available.
+   */
+  active$: Behavior<LocalTransportWithSFUConfig | null>;
+}
+
 /**
- * Connects to the JWT service and determines the transport that the local member should use.
+ * Connects to the JWT service and determines the transports that the local member should use.
  *
  * @prop useOldJwtEndpoint Whether to set forceOldJwtEndpoint on the returned transport and to use the old JWT endpoint.
  * This is used when the connection manager needs to know if it has to use the legacy endpoint which implies a string concatenated rtcBackendIdentity.
  * (which is expected for non sticky event based rtc member events)
- * @returns The transport to advertise in our MatrixRTC membership and publish media on.
+ * @returns The transport to advertise in the local MatrixRTC membership, along with the transport to actively publish media to.
  * @throws MatrixRTCTransportMissingError | FailToGetOpenIdToken
  */
-export async function getLocalTransport({
+export const createLocalTransport$ = ({
+  scope,
+  memberships$,
   ownMembershipIdentity,
   client,
   roomId,
   matrixRTCMode,
-}: Props): Promise<LocalTransport> {
+}: Props): LocalTransport => {
   const logger = rootLogger.getChild("[LocalTransport]");
-  const discovery = new RtcTransportAutoDiscovery({
+
+  const transportDiscovery = new RtcTransportAutoDiscovery({
     client: client,
     resolvedConfig: Config.get(),
     logger: logger,
   });
-  const customUrl = customLivekitUrl.value$.value;
 
-  // Respect the user's custom URL, if set
-  const transport: LivekitTransportConfig | null = customUrl
-    ? { type: "livekit", livekit_service_url: customUrl }
-    : await discovery.discoverPreferredTransport();
+  // Get the preferred transport from the current deployment.
+  const discoveredTransport$ = from(
+    transportDiscovery.discoverPreferredTransport(),
+  );
 
-  if (transport === null)
-    throw new MatrixRTCTransportMissingError(client.getDomain() ?? "");
+  const preferredConfig$ = customLivekitUrl.value$.pipe(
+    switchMap((customUrl) => {
+      if (customUrl) {
+        return of({
+          type: "livekit",
+          livekit_service_url: customUrl,
+        } as LivekitTransportConfig);
+      } else {
+        return discoveredTransport$;
+      }
+    }),
+    map((config) => {
+      if (!config) {
+        // Bubbled up from the preferredConfig$ observable.
+        throw new MatrixRTCTransportMissingError(client.getDomain() ?? "");
+      }
+      return config;
+    }),
+    distinctUntilChanged(areLivekitTransportsEqual),
+  );
 
-  try {
-    return await doOpenIdAndJWTFromUrl(
-      transport,
-      matrixRTCMode,
-      ownMembershipIdentity,
-      roomId,
-      client,
-      logger,
-    );
-  } catch (e) {
-    logger.error(
-      `Failed to authenticate to transport ${transport.livekit_service_url}`,
-      e,
-    );
-    throw mapAuthErrorToUserFriendlyError(e);
-  }
-}
+  const preferredTransport$ = preferredConfig$.pipe(
+    switchMap(async (transport) => {
+      try {
+        return await doOpenIdAndJWTFromUrl(
+          transport,
+          matrixRTCMode,
+          ownMembershipIdentity,
+          roomId,
+          client,
+          logger,
+        );
+      } catch (e) {
+        logger.error(
+          `Failed to authenticate to transport ${transport.livekit_service_url}`,
+          e,
+        );
+        throw mapAuthErrorToUserFriendlyError(e);
+      }
+    }),
+  );
+
+  // Always publish on and advertise the preferred transport.
+  return {
+    advertised$: scope.behavior(
+      preferredTransport$.pipe(
+        map((t) => t.transport),
+        distinctUntilChanged(areLivekitTransportsEqual),
+      ),
+      null,
+    ),
+    active$: scope.behavior(preferredTransport$, null),
+  };
+};
 
 /**
  *  Utility to ensure the user can authenticate with the SFU.
@@ -137,7 +199,7 @@ async function doOpenIdAndJWTFromUrl(
   roomId: string,
   client: Pick<MatrixClient, "_unstable_getRTCTransports"> & OpenIDClientParts,
   logger?: Logger,
-): Promise<LocalTransport> {
+): Promise<LocalTransportWithSFUConfig> {
   const sfuConfig = await getSFUConfigWithOpenID(
     client,
     membership,

src/state/CallViewModel/remoteMembers/ConnectionManager.test.ts

@@ -6,7 +6,7 @@ Please see LICENSE in the repository root for full details.
 */
 
 import { afterEach, beforeEach, describe, expect, test, vi } from "vitest";
-import { BehaviorSubject, NEVER } from "rxjs";
+import { BehaviorSubject } from "rxjs";
 import { type LivekitTransportConfig } from "matrix-js-sdk/lib/matrixrtc";
 import { type RemoteParticipant } from "livekit-client";
 import { logger } from "matrix-js-sdk/lib/logger";
@@ -20,7 +20,7 @@ import { type ConnectionFactory } from "./ConnectionFactory.ts";
 import { type Connection } from "./Connection.ts";
 import { ownMemberMock, withTestScheduler } from "../../../utils/test.ts";
 import { areLivekitTransportsEqual } from "./MatrixLivekitMembers.ts";
-import { type Behavior } from "../../Behavior.ts";
+import { constant, type Behavior } from "../../Behavior.ts";
 
 // Some test constants
 
@@ -74,7 +74,7 @@ describe("connections$ stream", () => {
       const { connectionManagerData$ } = createConnectionManager$({
         scope: testScope,
         connectionFactory: fakeConnectionFactory,
-        localTransport$: NEVER,
+        localTransport$: constant(null),
         remoteTransports$: behavior("a", {
           a: new Epoch([TRANSPORT_1, TRANSPORT_2], 0),
         }),
@@ -115,7 +115,7 @@ describe("connections$ stream", () => {
       const { connectionManagerData$ } = createConnectionManager$({
         scope: testScope,
         connectionFactory: fakeConnectionFactory,
-        localTransport$: NEVER,
+        localTransport$: constant(null),
         remoteTransports$: behavior("abcdef", {
           a: new Epoch([TRANSPORT_1], 0),
           b: new Epoch([TRANSPORT_1], 1),
@@ -162,7 +162,7 @@ describe("connections$ stream", () => {
       const { connectionManagerData$ } = createConnectionManager$({
         scope: testScope,
         connectionFactory: fakeConnectionFactory,
-        localTransport$: NEVER,
+        localTransport$: constant(null),
         remoteTransports$: behavior("abc", {
           a: new Epoch([TRANSPORT_1], 0),
           b: new Epoch([TRANSPORT_1, TRANSPORT_2], 1),
@@ -297,7 +297,7 @@ describe("connectionManagerData$ stream", () => {
       const { connectionManagerData$ } = createConnectionManager$({
         scope: testScope,
         connectionFactory: fakeConnectionFactory,
-        localTransport$: NEVER,
+        localTransport$: constant(null),
         remoteTransports$: behavior("a", {
           a: new Epoch([TRANSPORT_1, TRANSPORT_2], 0),
         }),

src/state/CallViewModel/remoteMembers/ConnectionManager.ts

@@ -7,16 +7,7 @@ Please see LICENSE in the repository root for full details.
 */
 
 import { type LivekitTransportConfig } from "matrix-js-sdk/lib/matrixrtc";
-import {
-  combineLatest,
-  map,
-  type Observable,
-  of,
-  switchMap,
-  startWith,
-  catchError,
-  NEVER,
-} from "rxjs";
+import { combineLatest, map, of, switchMap } from "rxjs";
 import { type Logger } from "matrix-js-sdk/lib/logger";
 import { type RemoteParticipant } from "livekit-client";
 import { type CallMembershipIdentityParts } from "matrix-js-sdk/lib/matrixrtc/EncryptionManager";
@@ -28,8 +19,8 @@ import { generateItemsWithEpoch } from "../../../utils/observable.ts";
 import { areLivekitTransportsEqual } from "./MatrixLivekitMembers.ts";
 import { type ConnectionFactory } from "./ConnectionFactory.ts";
 import {
-  isLocalTransport,
-  type LocalTransport,
+  isLocalTransportWithSFUConfig,
+  type LocalTransportWithSFUConfig,
 } from "../localMember/LocalTransport.ts";
 import { type SFUConfig } from "../../../livekit/openIDSFU.ts";
 
@@ -87,7 +78,7 @@ export class ConnectionManagerData {
 interface Props {
   scope: ObservableScope;
   connectionFactory: ConnectionFactory;
-  localTransport$: Observable<LocalTransport>;
+  localTransport$: Behavior<LocalTransportWithSFUConfig | null>;
   remoteTransports$: Behavior<Epoch<LivekitTransportConfig[]>>;
 
   logger: Logger;
@@ -130,14 +121,6 @@ export function createConnectionManager$({
   const logger = parentLogger.getChild("[ConnectionManager]");
   // TODO logger: only construct one logger from the client and make it compatible via a EC specific sing
 
-  const localTransportAsArray$ = localTransport$.pipe(
-    // LocalMember already surfaces local transport errors properly in the UI,
-    // here we can just swallow them
-    catchError(() => NEVER),
-    map((transport) => [transport]),
-    startWith([]),
-  );
-
   /**
    * All transports currently managed by the ConnectionManager.
    *
@@ -147,12 +130,16 @@ export function createConnectionManager$({
    * externally this is modified via `registerTransports()`.
    */
   const localAndRemoteTransports$: Behavior<
-    Epoch<(LivekitTransportConfig | LocalTransport)[]>
+    Epoch<(LivekitTransportConfig | LocalTransportWithSFUConfig)[]>
   > = scope.behavior(
-    combineLatest([localTransportAsArray$, remoteTransports$]).pipe(
+    combineLatest([remoteTransports$, localTransport$]).pipe(
       // Combine local and remote transports into one transport array
       // and set the forceOldJwtEndpoint property on the local transport
-      map(([localTransportAsArray, remoteTransports]) => {
+      map(([remoteTransports, localTransport]) => {
+        let localTransportAsArray: LocalTransportWithSFUConfig[] = [];
+        if (localTransport) {
+          localTransportAsArray = [localTransport];
+        }
         const dedupedRemote = removeDuplicateTransports(remoteTransports.value);
         const remoteWithoutLocal = dedupedRemote.filter(
           (transport) =>
@@ -183,9 +170,8 @@ export function createConnectionManager$({
         "ConnectionManager connections$",
         function* (transports) {
           for (const transport of transports) {
-            if (isLocalTransport(transport)) {
-              // This is the local transport; only the `LocalTransport`
-              // interface has a `sfuConfig` field.
+            if (isLocalTransportWithSFUConfig(transport)) {
+              // This is the local transport; only the `LocalTransportWithSFUConfig` has a `sfuConfig` field.
               yield {
                 keys: [
                   transport.transport.livekit_service_url,

src/state/CallViewModel/remoteMembers/integration.test.ts

@@ -6,7 +6,7 @@ Please see LICENSE in the repository root for full details.
 */
 
 import { test, vi, expect, beforeEach, afterEach } from "vitest";
-import { BehaviorSubject, NEVER } from "rxjs";
+import { BehaviorSubject } from "rxjs";
 import { type Room as LivekitRoom } from "livekit-client";
 import EventEmitter from "events";
 import fetchMock from "fetch-mock";
@@ -34,6 +34,7 @@ import {
 } from "./MatrixLivekitMembers.ts";
 import { createConnectionManager$ } from "./ConnectionManager.ts";
 import { membershipsAndTransports$ } from "../../SessionBehaviors.ts";
+import { constant } from "../../Behavior.ts";
 import { localRtcMember, testJWTToken } from "../../../utils/test-fixtures.ts";
 
 // Test the integration of ConnectionManager and MatrixLivekitMerger
@@ -123,7 +124,7 @@ test("bob, carl, then bob joining no tracks yet", () => {
     const connectionManager = createConnectionManager$({
       scope: testScope,
       connectionFactory: ecConnectionFactory,
-      localTransport$: NEVER,
+      localTransport$: constant(null),
       remoteTransports$: membershipsAndTransports.transports$,
       logger: logger,
       ownMembershipIdentity: ownMemberMock,

src/state/SessionBehaviors.ts

@@ -22,10 +22,6 @@ import {
 } from "./ObservableScope";
 import { type Behavior } from "./Behavior";
 
-/**
- * Tracks the transports used by ourselves, plus all other MatrixRTC session
- * members.
- */
 export const membershipsAndTransports$ = (
   scope: ObservableScope,
   memberships$: Behavior<Epoch<CallMembership[]>>,
@@ -35,6 +31,14 @@ export const membershipsAndTransports$ = (
   >;
   transports$: Behavior<Epoch<LivekitTransportConfig[]>>;
 } => {
+  /**
+   * Lists the transports used by ourselves, plus all other MatrixRTC session
+   * members.
+   * For completeness this also lists the preferred transport and
+   * whether we are in multi-SFU mode or sticky events mode.
+   * `advertisedTransport$` reads these values together, so bundling them avoids inconsistent state or
+   * excessive updates when using RxJS.
+   */
   const membershipsWithTransport$: Behavior<
     Epoch<
       {

src/utils/observable.test.ts

@@ -9,9 +9,30 @@ import { expect, test } from "vitest";
 import { type Observable, of, Subject, switchMap } from "rxjs";
 
 import { withTestScheduler } from "./test";
-import { filterBehavior, generateItems, pauseWhen } from "./observable";
+import { or$, filterBehavior, generateItems, pauseWhen } from "./observable";
 import { type Behavior } from "../state/Behavior";
 
+const yesNo = {
+  y: true,
+  n: false,
+};
+
+test("or$", () => {
+  withTestScheduler(({ behavior, expectObservable }) => {
+    const input1Marbles = "ny--n--";
+    const input2Marbles = "n-y--n-";
+    const input3Marbles = "n--y--n";
+    const outputMarbles = "nyyyyyn";
+    expectObservable(
+      or$(
+        behavior(input1Marbles, yesNo),
+        behavior(input2Marbles, yesNo),
+        behavior(input3Marbles, yesNo),
+      ),
+    ).toBe(outputMarbles, yesNo);
+  });
+});
+
 test("pauseWhen", () => {
   withTestScheduler(({ behavior, expectObservable }) => {
     const inputMarbles = " abcdefgh-i-jk-";

src/utils/observable.ts

@@ -8,6 +8,7 @@ Please see LICENSE in the repository root for full details.
 import {
   type Observable,
   audit,
+  combineLatest,
   concat,
   defer,
   filter,
@@ -112,6 +113,14 @@ export function getValue<T>(state$: Observable<T>): T {
   return value;
 }
 
+/**
+ * Creates an Observable that has a value of true whenever some of its inputs
+ * are true.
+ */
+export function or$(...inputs: Observable<boolean>[]): Observable<boolean> {
+  return combineLatest(inputs, (...flags) => flags.some((flag) => flag));
+}
+
 /**
  * RxJS operator that pauses all changes in the input value whenever a Behavior
  * is true. When the Behavior returns to being false, the most recently

vite-component-dev.config.ts

@@ -9,7 +9,7 @@ import { defineConfig, searchForWorkspaceRoot } from "vite";
 import { realpathSync } from "node:fs";
 import * as fs from "node:fs";
 
-import { vitePluginsConfig } from "./vite.config.ts";
+import { vitePluginsConfig } from "./vite.config";
 import { scopeStylesToRoot } from "./component/build/scopeStylesToRoot";
 
 // Serves the harness under `component/dev`, which embeds Element Call as a

vite-component.config.ts

@@ -7,7 +7,7 @@ Please see LICENSE in the repository root for full details.
 
 import { defineConfig } from "vite";
 
-import { vitePluginsConfig } from "./vite.config.ts";
+import { vitePluginsConfig } from "./vite.config";
 import { scopeStylesToRoot } from "./component/build/scopeStylesToRoot";
 
 // Config for Element Call as a React component, to be imported by an
@@ -49,8 +49,19 @@ export default defineConfig(({ mode }) => {
       cssCodeSplit: false,
       lib: {
         formats: ["es" as const],
-        entry: "./component/index.tsx",
-        fileName: "element-call",
+        entry: {
+          // The component
+          "element-call": "./component/index.tsx",
+          // What a host needs to talk about it, without it (see component/api.ts).
+          // Built as an entry point of its own so that importing it does not
+          // load the component: the bundler gives it a chunk that reaches only
+          // what it imports.
+          api: "./component/api.ts",
+        },
+        fileName: (_format, entryName) => `${entryName}.js`,
+        // The one stylesheet (see cssCodeSplit) keeps the name it had when the
+        // component was the only entry
+        cssFileName: "element-call",
       },
       rollupOptions: {
         // The host already has these, and a second copy of any of them does not

vite-embedded.config.ts

@@ -8,7 +8,7 @@ Please see LICENSE in the repository root for full details.
 import { defineConfig, mergeConfig } from "vite";
 import generateFile from "vite-plugin-generate-file";
 
-import fullConfig from "./vite.config.ts";
+import fullConfig from "./vite.config";
 
 const base = "./";
 

vitest.config.ts

@@ -1,6 +1,6 @@
 import { defineConfig, mergeConfig } from "vitest/config";
 import { playwright } from "@vitest/browser-playwright";
-import { vitePluginsConfig } from "./vite.config.ts";
+import { vitePluginsConfig } from "./vite.config";
 import { storybookTest } from "@storybook/addon-vitest/vitest-plugin";
 import path from "node:path";
 import { fileURLToPath } from "node:url";