JavaScript Actions in GitHub Actions

Introduction

JavaScript Actions allow you to write reusable code that can be run in the context of a GitHub Actions workflow. These actions can perform various tasks, such as setting up an environment, running tests, or deploying applications.

What are JavaScript Actions?

JavaScript Actions are custom actions written in JavaScript, enabling developers to encapsulate logic and reuse it across workflows. They can be published to the GitHub Marketplace and shared with the community.

Creating a JavaScript Action

The process of creating a JavaScript Action involves the following steps:

1. Set up your project directory.
2. Create an index.js file to contain your action's logic.
3. Define the action's metadata in a action.yml file.
4. Publish your action to the GitHub Marketplace (optional).

Step 1: Set up your project directory

mkdir my-javascript-action
cd my-javascript-action
npm init -y
    

Step 2: Create the index.js file

This file will contain the logic for your action. Here is a simple example:

const core = require('@actions/core');

async function run() {
    try {
        const name = core.getInput('name');
        console.log(`Hello ${name}!`);
        core.setOutput('time', new Date().toTimeString());
    } catch (error) {
        core.setFailed(error.message);
    }
}

run();
    

Step 3: Define the action's metadata in action.yml

name: 'My JavaScript Action'
description: 'A simple greeting action'
inputs:
    name:
        description: 'Who to greet'
        required: true
        default: 'World'
runs:
    using: 'node12'
    main: 'index.js'
    

Step 4: Publish your action (optional)

Once your action is ready, you can publish it to the GitHub Marketplace, allowing others to use it in their workflows.

Best Practices

• Use descriptive names and descriptions for your actions.
• Handle errors gracefully and provide meaningful messages.
• Document your action clearly in the README.md file.
• Keep your dependencies updated to avoid security vulnerabilities.

FAQ