Circle CI config for Create React App

config.yml

version: 2
jobs:
  build:
    docker:
      - image: circleci/node:10.11.0
    steps:
      - checkout
      - restore_cache:
          key: dependency-cache-{{ checksum "yarn.lock" }}
      - run:
          name: Setup Dependencies
          command: yarn install
      - save_cache:
          key: dependency-cache-{{ checksum "yarn.lock" }}
          paths:
            - ./node_modules
      - run:
          name: Run Test
          command: yarn test

Thanks! In the CircleCI docs, the restore_cache, and save_cache reference the package.json file instead of the yarn.lock file. I imagine we want to rebuild the cache when the yarn.lock file changes but I'm not confident. Do you happen to know when we want to watch the package.json file vs the yarn.lock file?

yarn.lock seems a bit safer to me, just since it represents exactly which dependencies to download.

At least in my case, there are times when the package.json doesn't change, but the yarn.lock does, since we have a dependency on another internal GitHub repo that isn't versioned. When we upgrade that dependency via yarn upgrade ..., the package.json stays unchanged, but the lockfile changes, pointing to the latest git commit of that dependency.

You could always watch both I think with dependency-cache-{{ checksum "yarn.lock" }}-{{ checksum "package.json" }} to be extra safe. Hope that helps!

super helpful, thank you! 🌸