How to cache yarn packages in GitHub Actions

Question

I am using GitHub Actions to build my TypeScript project. Everytime I run action I am waiting 3 minutes for all dependencies to get installed.

Is there way to cache

Answer 1

As mentioned in the comment next to the id field for the caching step:

Use this to check for cache-hit (steps.yarn-cache.outputs.cache-hit != 'true')

You're missing a conditional if property that determines whether the step should be run:

- name: Install yarn
  run: npm install -g yarn

- name: Install project dependencies
  if: steps.yarn-cache.outputs.cache-hit != 'true' # Over here!
  run: yarn

P.S. You should probably use the Setup NodeJS GitHub Action that additionally sets up Yarn for you:

- uses: actions/setup-node@v1
  with:
    node-version: '10.x' # The version spec of the version to use.

See the action.yml file for a full list of valid inputs.

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EDIT: As it turns out, Yarn is included in the list of software installed on the GitHub-hosted Ubuntu 18.04.4 LTS (ubuntu-latest/ubuntu-18.04) runner, so there's no need to include a step to globally install Yarn.