Files
element-call-Github/src/useStableValue.test.ts
T
Timo K.andClaude Fable 5.1 a010cc983f Compare the component's config by value
Everything downstream of the component's params — the mute state, the
call view model and with it the media connection — is keyed on the
identity of the params object, which was memoised on the identity of
the `config` prop. A host writing `config={{ ... }}` inline, which is
the natural way to write it, therefore tore the whole call down on
every render. The harness happened to pass a constant, so nothing
noticed.

`useStableValue` hands out the same object for as long as a deep
comparison says nothing changed, so an inline config costs nothing.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
2026-09-08 13:49:19 +02:00

65 lines
2.0 KiB
TypeScript

/*
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.
*/
import { renderHook } from "@testing-library/react";
import { describe, expect, test } from "vitest";
import { useStableValue } from "./useStableValue";
describe("useStableValue", () => {
test("keeps the first identity while the contents stay equal", () => {
const first = { skipLobby: true, fonts: ["Inter"] };
const { result, rerender } = renderHook(
({ value }) => useStableValue(value),
{ initialProps: { value: first } },
);
expect(result.current).toBe(first);
rerender({ value: { skipLobby: true, fonts: ["Inter"] } });
expect(result.current).toBe(first);
});
test("takes the new identity once the contents change", () => {
const first = { skipLobby: true };
const second = { skipLobby: false };
const { result, rerender } = renderHook(
({ value }) => useStableValue(value),
{ initialProps: { value: first } },
);
rerender({ value: second });
expect(result.current).toBe(second);
// And that identity is then the stable one
rerender({ value: { skipLobby: false } });
expect(result.current).toBe(second);
});
test("handles undefined, for an optional prop left out", () => {
const { result, rerender } = renderHook(
({ value }) => useStableValue(value),
{ initialProps: { value: undefined as { a: number } | undefined } },
);
expect(result.current).toBeUndefined();
const given = { a: 1 };
rerender({ value: given });
expect(result.current).toBe(given);
});
test("accepts its own notion of equality", () => {
const first = { id: 1, label: "a" };
const { result, rerender } = renderHook(
({ value }) => useStableValue(value, (a, b) => a.id === b.id),
{ initialProps: { value: first } },
);
rerender({ value: { id: 1, label: "b" } });
expect(result.current).toBe(first);
});
});