The simplest CircleCI 2.1 config example for Node / JS projects

config.yml

## References:
# https://git.io/Jf3l9
# https://circleci.com/docs/2.0/yarn/
# https://circleci.com/docs/2.0/caching/#yarn-node
# https://circleci.com/orbs/registry/orb/circleci/node
# https://discuss.circleci.com/t/circleci-2-1-config-overview/26057
version: 2.1

orbs:
  node: circleci/node@2.0.3

commands:
  setup-node-and-yarn-install-with-cache:
    steps:
      - node/install:
          install-yarn: true
          node-version: latest
      - node/install-packages:
          pkg-manager: yarn
          cache-key: yarn.lock

jobs:
  lint-and-test:
    executor:
      name: node/default
    steps:
      - checkout
      - setup-node-and-yarn-install-with-cache
      - run:
          name: Lint
          command: npm run lint
      - run:
          name: Check types
          command: npm run check-types
      - run:
          name: Run tests
          command: npm run test

workflows:
  run-ci:
    jobs:
      - lint-and-test

https://circleci.com/developer/orbs/orb/circleci/node

Maybe we could see the default orbs provider:

version: '2.1'
orbs:
  node: circleci/node@4.7.0

jobs:
  test:
    executor:
      name: node/default
      tag: '14.17.6'
    steps:
      - checkout
      - node/install-packages
      - run:
          command: npm run test