Introduction to npm-run-all

Npm-run-all is a powerful tool utilized in Node.js projects to optimize script management and achieve parallel and sequential task execution. It simplifies the process of running multiple npm scripts, making your development workflow more efficient.

How to Install npm-run-all

  npm install npm-run-all --save-dev

Running Scripts Sequentially

The npm-run-all command provides an easy way to run multiple scripts sequentially.

  npm-run-all script1 script2 script3

Running Scripts in Parallel

In addition to sequential execution, you can run multiple scripts in parallel using the -p flag.

  npm-run-all -p script1 script2 script3

Combining Parallel and Sequential Execution

You can mix parallel and sequential script execution for greater flexibility.

  npm-run-all -p script1 script2 --parallel-task-sequence "script3 script4" --parallel-task-sequence "script5 script6"

Examples of npm-run-all Usage

Example 1: Build and Watch

  {
    "scripts": {
      "build": "webpack --config webpack.config.js",
      "watch": "webpack --watch",
      "start": "npm-run-all build watch"
    }
  }

Example 2: Testing and Linting

  {
    "scripts": {
      "test": "jest",
      "lint": "eslint .",
      "test-and-lint": "npm-run-all test lint"
    }
  }

Sample Application Using npm-run-all

Let’s build a small application to demonstrate the use of npm-run-all.

Step 1: Project Setup

  mkdir my-app
  cd my-app
  npm init -y
  npm install express
  npm install npm-run-all --save-dev

Step 2: Create Scripts in package.json

  {
    "scripts": {
      "serve": "node server.js",
      "lint": "eslint .",
      "test": "jest",
      "start": "npm-run-all lint test serve"
    }
  }

Step 3: Create server.js

  const express = require('express');
  const app = express();
  const port = 3000;
  
  app.get('/', (req, res) => {
    res.send('Hello World!');
  });
  
  app.listen(port, () => {
    console.log(`Example app listening at http://localhost:${port}`);
  });

Step 4: Run the Application

  npm run start

By using npm-run-all, we can ensure our application’s scripts are run in sequence, making development more efficient. Happy coding!

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