# Developing with linked packages

If you want to make changes to a package that Element Call depends on and see those changes applied in real time, you can create a link to a local copy of the package. Pnpm has a command for this (`pnpm link`), but it's not recommended to use it as it ends up modifying package.json with details specific to your development environment.

Instead, you can use our little 'linker' plugin. Create a file named `.links.cjs` in the Element Call project directory, listing the names and paths of any dependencies you want to link. For example:

```cjs
// Packages to link to local checkouts
module.exports = {
  "matrix-js-sdk": "../your/path/matrix-js-sdk",
  "matrix-widget-api": "../your/path/matrix-widget-api",
};
```

Then run `pnpm install`.

## Hooks

Changes in `.links.yaml` will also update `pnpm-lock.yaml` when `pnpm` is executed. The lockfile will then contain the local
version of the package which would not work on others dev setups or the github CI.

One always needs to run:

```bash
mv .links.cjs .links.disabled.cjs
pnpm install
```

before committing a change.

To make it more convenient to work with this linking system we added git hooks.
A `pre-commit` hook will run `mv .links.yaml .links.disabled.yaml`, `pnpm install` and `git add yarn.lock` if it detects
a `.links.yaml` file and abort the commit.
You will than need to check if the resulting changes are appropriate and commit again.

A `post-commit` hook will setup the linking as it was
before if a `.links.disabled.cjs` is present. It runs `mv .links.disabled.cjs .links.cjs` and `pnpm install`.

To activate the hooks automatically configure git with

```bash
git config --local core.hooksPath .githooks
```