Package Managers

Package Managers

NPM

Node Package Manager provides two main functionalities:

• It provides online repositories for Node.js packages/modules which are searchable on search.nodejs.org
• It also provides command line utility to install Node.js packages, do version management and dependency management of Node.js packages.

The npm comes bundled with Node.js installables in versions after that v0.6.3. You can check the version by opening Node.js command prompt and typing the following command:

npm -v

Generating a package.json

You can use npm init to create the package.json. It will prompt you for values for the package.json fields. The two required fields are name and version. You’ll also want to have a value for main. You can use the default, index.js, or add your own like main.js or app.js.

To understand each value of the package.json file, I strongly recommend this interactive guide.

Installing Modules

Following is the syntax to install any Node.js module:

npm install <module name>

for example

npm install express

Uninstalling Modules

To uninstall a Node.js module, use the following command:

npm uninstall <module name>

for example

npm uninstall express

Global vs. Local installation

By default, npm installs dependency in local mode. Here local mode specifies the folder where Node application is present. For example if you installed express module, it created node_modules directory in the current directory where it installed express module.

You can install a local package like a developer dependecy to avoid adding that package into the production build, it’s very used for linters, testing tools and everything that shouldn’t be in the production bundle.

npm install mocha --save-dev

Globally installed packages/dependencies are stored in system directory. Let’s install express module using global installation. Although it will also produce the same result but modules will be installed globally.

You can install a global package by adding the -g flag in the install command

npm install -g typescript

Yarn

Yarn is a new package manager for JavaScript developed by Facebook.

The easiest way to get started is to run:

npm install -g yarn
yarn

The yarn CLI replaces npm in your development workflow, either with a matching command or a new, similar command:

npm install → yarn

npm install --save <module name> → yarn add <module name>

npm install --save-dev <module name> → yarn add <module name> --dev

CLI commands comparison