Understanding NPM Install and NPM Run Scripts

NPM (Node Package Manager) is a crucial tool for managing dependencies and running scripts in Node.js projects. Two commonly used commands in NPM are npm install and npm run. In this tutorial, we will explore the differences between these two commands and how they work.

Introduction to NPM Install

The npm install command is used to install dependencies specified in the package.json file of a project. When you run npm install, NPM downloads and installs all the dependencies listed in the dependencies field of the package.json file. This ensures that your project has all the necessary dependencies to run correctly.

Introduction to NPM Run

The npm run command is used to execute scripts defined in the scripts field of the package.json file. These scripts can be custom commands that perform specific tasks, such as building the project, running tests, or starting the application. When you run npm run <script-name>, NPM executes the corresponding script.

Key Differences

The main difference between npm install and npm run is their purpose:

• npm install installs dependencies specified in the package.json file.
• npm run executes custom scripts defined in the scripts field of the package.json file.

Another important difference is that npm install will also execute the install script defined in the scripts field, if present. However, npm run install will only execute the install script and will not install dependencies.

NPM Build

It’s worth noting that there is a command called npm build, but it is an internal command used by NPM to build native C/C++ Node addons using node-gyp. You should not use this command directly, instead, define a custom build script in your package.json file and run it using npm run build.

Example Package.json File

Here’s an example of a package.json file with some scripts defined:

{
    "name": "demo",
    "version": "1.0.0",
    "description": "",
    "main": "index.js",
    "scripts": {
        "build": "echo 'hello build'",
        "start": "node server.js"
    },
    "keywords": [],
    "author": "",
    "license": "ISC",
    "devDependencies": {},
    "dependencies": {}
}

In this example, you can run the build script using npm run build, and the start script using npm start.

Best Practices

When defining custom scripts in your package.json file, make sure to follow these best practices:

• Keep your scripts concise and focused on a single task.
• Use meaningful names for your scripts to make them easy to understand.
• Document your scripts in the README.md file of your project.

By following these guidelines and understanding the differences between npm install and npm run, you can effectively manage dependencies and automate tasks in your Node.js projects.

Common NPM Run Scripts

Here are some common NPM run scripts:

• npm start: Starts the application.
• npm test: Runs tests for the application.
• npm build: Builds the application (custom script).
• npm install: Installs dependencies specified in the package.json file.

Remember to define these scripts in your package.json file and use them accordingly to automate tasks in your project.