| # NPM Lockfile | |
| We use [`yarn.lock`](https://classic.yarnpkg.com/en/docs/yarn-lock/) | |
| to lock down our dependency versions. This allows us to freeze all dependencies at the | |
| exact version we have installed in our node_modules. | |
| ## Generating The Lockfile | |
| Yarn will automattically generate and update the lock file whenever `yarn`, `yarn install` or `yarn add` is called. If you've manually updated a `package.json` file then Yarn will update the lock file as necessary. | |
| ## Testing | |
| To verify that the new `yarn.lock` works: | |
| - Run `yarn run distclean` to delete local `node_modules` | |
| - Run `yarn install --immutable` | |
| - Verify that Calypso works as expected and that tests pass | |