NPM - Node Package Manager¶

What is NPM?¶

There are many modules/packages that you can add to your node project. Node Package Manager makes the process of installing and removing node packages easier and quicker.

Start a project¶

1. Create a directory called myproject. Go to that directory.
2. Type in the terminal npm init to initialize a new project.
3. The npm init command will create a configuration file for your project called package.json.
4. You will be prompted to provide information about your project. You can simply press enter for all the questions.
5. The basic package.json file looks like the following:

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC"
}

Installing packages¶

Task 1: Install a node package called http. Hint: type npm install http. Check package.json file after installing the module; did it change?

1. Run the command npm install http.
2. Notice that a new folder is created node_modules, and you can find a folder called http added within it.
3. Notice that the package.json file changes to the following:

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "http": "0.0.1-security"
  }
}

Task 2: Install a node package called express. Check package.json file after installing the module; did it change?

1. Run the command npm install express.
2. Notice that a new folder is created node_modules, and you can find a folder called express added within it.
3. Notice that the package.json file changes to the following:

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^4.17.1",
    "http": "0.0.1-security"
  }
}

Task 3: Install a node package called mustache. Check package.json file after installing the module; did it change?

1. Run the command npm install mustache.
2. Notice that a new folder is created node_modules, and you can find a folder called mustache added within it.
3. Notice that the package.json file changes to the following:

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^4.17.1",
    "http": "0.0.1-security",
    "mustache": "^4.2.0"
  }
}

Uninstalling packages¶

Task 1: Uninstall the http node module. Hint: type npm uninstall http. Check package.json file after installing the module; did it change?

1. Run the command npm uninstall http.
2. Notice that nodes_modules/http is deleted.
3. Notice that the package.json file changes to the following:

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "express": "^4.17.1",
    "mustache": "^4.2.0"
  }
}

Task 2: Uninstall the express node module. Check package.json file after installing the module; did it change?

1. Run the command npm uninstall express.
2. Notice that nodes_modules/express is deleted.
3. Notice that the package.json file changes to the following:

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "mustache": "^4.2.0"
  }
}

Task 3: Uninstall the mustache node module. Check package.json file after installing the module; did it change?

1. Run the command npm uninstall mustache.
2. Notice that nodes_modules/mustache is deleted.
3. Notice that the package.json file changes to the following:

{
  "name": "test",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
  }
}