Creating a JavaScript Action

The node12-template repo contains everything you need to get started.

Create a Repo from the Template

Navigate to https://github.com/actions/node12-template

Click on Use this template to create the repo for your action.

Complete creating your repo and clone the repo.

NOTE: The location of the repo will be how users will reference your action in their workflow file with the using keyword.

e.g. To use https://github.com/actions/setup-node, user's will author:

steps:
    using: actions/setup-node@master

Install Dependencies

This will install the toolkit and other dependencies

$ npm install

The production dependencies are vendored into your action. At runtime, the self contained action will be downloaded, extracted and run.

Define Metadata

Your action has a name and a description. Update the author.

Create inputs that your unit of work will need. These will be what workflow authors set with the with: keyword.

name: 'My new action'
description: 'A test action'
author: 'GitHub'
inputs: 
  myInput:
    description: 'Input to use'
    default: 'world'
runs:
  using: 'node12'
  main: 'lib/main.js'

Note that the action will be run with node 12 (carried by the runner) and the entry point is specified with main:

Change Code and Add Tests

The entry point is in main.ts

import * as core from '@actions/core';

async function run() {
  try {
    const myInput = core.getInput('myInput');
    core.debug(`Hello ${myInput}!`);
  } catch (error) {
    core.setFailed(error.message);
  }
}

run();

Modify tests in __tests__\main.test.ts. The template uses jest.

Format the Code

$ npm run format

Build and Test

$ npm run build

> node12-template-action@0.0.0 build /Users/user/Projects/testnode12
> tsc

$ npm test

> jest

 PASS  __tests__/main.test.ts
  TODO - Add a test suite
    ✓ TODO - Add a test (1ms)

Test Suites: 1 passed, 1 total
...

Commit and Push Changes

$ git add <whatever only files you added>
$ git commit -m "Message"

IMPORTANT: do not git add or .gitignore node_modules.

Husky will add/vendor node_modules and prune dev dependencies. See husky in package.json for details. There is no need for you to add node_modules.

NOTE: We understand that the process of checking in node_modules is currently somewhat painful for some use cases. We are actively tracking an enhancement in this issue to improve this process (and are open to any suggestions 😄).

In the meantime we still strongly encourage you to not check in dev-dependencies, it will significantly bloat the size of actions and degrade the experience.

Publish Action

Simply push your action to publish.

$ git push

NOTE: Consider versioning your actions with tags. See versioning

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