GitHub Action Script Best Practices

This skill provides guidelines for writing JavaScript files that run using the GitHub Action

actions/github-script@v8

.

Important Notes

• This action provides

  @actions/core

  and

  @actions/github

  packages globally
• Do not add import or require for

  @actions/core

• Reference documentation:
  • https://github.com/actions/toolkit/blob/main/packages/core/README.md
  • https://github.com/actions/toolkit/blob/main/packages/github/README.md

Best Practices

• Use

  core.info

  ,

  core.warning

  ,

  core.error

  for logging, not

  console.log

  or

  console.error

• Use

  core.setOutput

  to set action outputs
• Use

  core.exportVariable

  to set environment variables for subsequent steps
• Use

  core.getInput

  to get action inputs, with

  required: true

  for mandatory inputs
• Use

  core.setFailed

  to mark the action as failed with an error message

Step Summary

Use

core.summary.*

function to write output the step summary file.

• Use

  core.summary.addRaw()

  to add raw Markdown content (GitHub Flavored Markdown supported)
• Make sure to call

  core.summary.write()

  to flush pending writes
• Summary function calls can be chained, e.g.

  core.summary.addRaw(...).addRaw(...).write()

Common Errors

• Avoid

  any

  type as much as possible, use specific types or

  unknown

  instead
• Catch handler: check if error is an instance of Error before accessing message property

catch (error) {
  core.setFailed(error instanceof Error ? error : String(error));
}

• core.setFailed

  also calls

  core.error

  , so do not call both

Typechecking

Run

make js

to run the typescript compiler.

Run

make lint-cjs

to lint the files.

Run

make fmt-cjs

after editing to format the file.