Ensuring type safety is one of the most important responsibilities of modern software developers.

This action uses the TypeScript Compiler API to run a static type check on your code and display the results of the check.

.github/workflows/test.yml:

name: Test

on: [pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [13.x]
    steps:
      - uses: actions/checkout@v1
      - name: Use Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v1
        with:
          node-version: ${{ matrix.node-version }}
      - name: Install dependencies
        run: yarn install --frozen-lockfile
      - name: Typecheck
        uses: computerjazz/[email protected]

tsconfig.json:

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "strict": true,
    "skipLibCheck": true,
    "moduleResolution": "node",
    "types": ["node"],
    "lib": ["ES2017"]
  },
  "include": ["src/**/*.ts"]
}

If you're working with a monorepo or your tsconfig.json is not in the root repo, or you use different config file, you can provide a project parmeter with a path to the repo itself:

- name: Typecheck
  uses: computerjazz/[email protected]
  with:
    project: packages/subpackage/tsconfig.json

If you're incrementally adopting typescript in a project, you may not want to fail the entire workflow on a single typescript error. error_fail_threshold allows you to pass the maximum number of errors at which the step passes. Defaults to 0:

- name: Typecheck
  uses: computerjazz/[email protected]
  with:
    error_fail_threshold: 100

In order to bypass the maximum of 10 pull request annotations that a GitHub action can post, this action uploads all annotations in separate, batched api calls, which requires an API token:

- name: Typecheck
  uses: computerjazz/[email protected]
  with:
    error_fail_threshold: 100
    repo_token: "${{ secrets.GITHUB_TOKEN }}"