A GitHub action that compares the real cost of your JavaScript in every pull request

This action uses Size Limit (performance budget tool for JavaScript) to calculate the real cost of your JavaScript for end-users. The main features of this action are:

• Commenting pull requests with the comparison of Size Limit output.
• Rejecting a pull request if the cost exceeds the limit.

1. Install Size Limit choosing the scenario that fits you better (JS Application, Big Libraries or Small Libraries).
2. By default this action will try to build your PR by running build npm script located in your package.json. If something need to be done after dependencies are installed but before building postinstall npm script could be used. For example, using lerna:

"scripts": {
  "postinstall": "lerna bootstrap",
  "build": "lerna run build"
},

3. Define Size limit configuration. For example (inside package.json):

"size-limit": [
  {
    "path": "dist/index.js",
    "limit": "4500 ms"
  }
]

4. Add the following action inside .github/workflows/size-limit.yml

name: "size"
on:
  pull_request:
    branches:
      - master
jobs:
  size:
    runs-on: ubuntu-latest
    env:
      CI_JOB_NUMBER: 1
    steps:
      - uses: actions/checkout@v1
      - uses: andresz1/size-limit-action@v1
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}

You can optionally specify a custom npm script to run instead of the default build adding a build_script option to the yml workflow shown above.

with:
  github_token: ${{ secrets.GITHUB_TOKEN }}
  build_script: custom-build

5. You are now all set

Pull requests, feature ideas and bug reports are very welcome. We highly appreciate any feedback.