NPM
Node.js - npm
Node Package Manager (npm) provides following two main functionalities:
- Online repositories for node.js packages/modules which are searchable on search.nodejs.org
- Command line utility to install Node.js packages, do version management and dependency management of Node.js packages.
npm comes bundled with Node.js installables after v0.6.3 version. To verify the same, open console and type following command and see the result:
$ npm --version 2.7.1
If you are running old version of npm then its damn easy to update it to the latest version. Just use the following command from root:
$ sudo npm install npm -g /usr/bin/npm -> /usr/lib/node_modules/npm/bin/npm-cli.js [email protected] /usr/lib/node_modules/npm
Installing Modules using npm
There is a simple syntax to install any Node.js module:
$ npm install
For example, following is the command to install a famous Node.js web framework module called express:
var express = require('express');
Global vs Local installation
By default, npm installs any dependency in the local mode. Here local mode refers to the package installation in node_modules directory lying in the folder where Node application is present. Locally deployed packages are accessible via require() method. For example when we installed express module, it created node_modules directory in the current directory where it installed express module.
$ ls -l total 0 drwxr-xr-x 3 root root 20 Mar 17 02:23 node_modules
Alternatively you can use npm ls command to list down all the locally installed modules.
Globally installed packages/dependencies are stored in system directory. Such dependencies can be used in CLI (Command Line Interface) function of any node.js but can not be imported using require() in Node application directly. Now Let's try installing express module using global installation.
$ npm install express -g
This will produce similar result but module will be installed globally. Here first line tells about the module version and its location where it is getting installed.
[email protected] /usr/lib/node_modules/express ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ├── [email protected] ([email protected]) ├── [email protected] ([email protected]) ├── [email protected] ([email protected]) ├── [email protected] ([email protected], [email protected]) ├── [email protected] ([email protected], [email protected], [email protected]) ├── [email protected] ([email protected]) ├── [email protected] ([email protected], [email protected]) └── [email protected] ([email protected], [email protected])
You can use following command to check all the modules installed globally:
$ npm ls -g
Using package.json
package.json is present in the root directory of any Node application/module and is used to define the properties of a package. Let's open package.json of express package present innode_modules/express/
{
"name": "express",
"description": "Fast, unopinionated, minimalist web framework",
"version": "4.11.2",
"author": {
"name": "TJ Holowaychuk",
"email": "[email protected]"
},
"contributors": [
{
"name": "Aaron Heckmann",
"email": "[email protected]"
},
{
"name": "Ciaran Jessup",
"email": "[email protected]"
},
{
"name": "Douglas Christopher Wilson",
"email": "[email protected]"
},
{
"name": "Guillermo Rauch",
"email": "[email protected]"
},
{
"name": "Jonathan Ong",
"email": "[email protected]"
},
{
"name": "Roman Shtylman",
"email": "[email protected]"
},
{
"name": "Young Jae Sim",
"email": "[email protected]"
}
],
"license": "MIT",
"repository": {
"type": "git",
"url": "https://github.com/strongloop/express"
},
"homepage": "http://expressjs.com/",
"keywords": [
"express",
"framework",
"sinatra",
"web",
"rest",
"restful",
"router",
"app",
"api"
],
"dependencies": {
"accepts": "~1.2.3",
"content-disposition": "0.5.0",
"cookie-signature": "1.0.5",
"debug": "~2.1.1",
"depd": "~1.0.0",
"escape-html": "1.0.1",
"etag": "~1.5.1",
"finalhandler": "0.3.3",
"fresh": "0.2.4",
"media-typer": "0.3.0",
"methods": "~1.1.1",
"on-finished": "~2.2.0",
"parseurl": "~1.3.0",
"path-to-regexp": "0.1.3",
"proxy-addr": "~1.0.6",
"qs": "2.3.3",
"range-parser": "~1.0.2",
"send": "0.11.1",
"serve-static": "~1.8.1",
"type-is": "~1.5.6",
"vary": "~1.0.0",
"cookie": "0.1.2",
"merge-descriptors": "0.0.2",
"utils-merge": "1.0.0"
},
"devDependencies": {
"after": "0.8.1",
"ejs": "2.1.4",
"istanbul": "0.3.5",
"marked": "0.3.3",
"mocha": "~2.1.0",
"should": "~4.6.2",
"supertest": "~0.15.0",
"hjs": "~0.0.6",
"body-parser": "~1.11.0",
"connect-redis": "~2.2.0",
"cookie-parser": "~1.3.3",
"express-session": "~1.10.2",
"jade": "~1.9.1",
"method-override": "~2.3.1",
"morgan": "~1.5.1",
"multiparty": "~4.1.1",
"vhost": "~3.0.0"
},
"engines": {
"node": ">= 0.10.0"
},
"files": [
"LICENSE",
"History.md",
"Readme.md",
"index.js",
"lib/"
],
"scripts": {
"test": "mocha --require test/support/env --reporter spec --bail --check-leaks test/ test/acceptance/",
"test-cov": "istanbul cover node_modules/mocha/bin/_mocha -- --require test/support/env --reporter dot --check-leaks test/ test/acceptance/",
"test-tap": "mocha --require test/support/env --reporter tap --check-leaks test/ test/acceptance/",
"test-travis": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --require test/support/env --reporter spec --check-leaks test/ test/acceptance/"
},
"gitHead": "63ab25579bda70b4927a179b580a9c580b6c7ada",
"bugs": {
"url": "https://github.com/strongloop/express/issues"
},
"_id": "[email protected]",
"_shasum": "8df3d5a9ac848585f00a0777601823faecd3b148",
"_from": "express@*",
"_npmVersion": "1.4.28",
"_npmUser": {
"name": "dougwilson",
"email": "[email protected]"
},
"maintainers": [
{
"name": "tjholowaychuk",
"email": "[email protected]"
},
{
"name": "jongleberry",
"email": "[email protected]"
},
{
"name": "shtylman",
"email": "[email protected]"
},
{
"name": "dougwilson",
"email": "[email protected]"
},
{
"name": "aredridel",
"email": "[email protected]"
},
{
"name": "strongloop",
"email": "[email protected]"
},
{
"name": "rfeng",
"email": "[email protected]"
}
],
"dist": {
"shasum": "8df3d5a9ac848585f00a0777601823faecd3b148",
"tarball": "http://registry.npmjs.org/express/-/express-4.11.2.tgz"
},
"directories": {},
"_resolved": "https://registry.npmjs.org/express/-/express-4.11.2.tgz",
"readme": "ERROR: No README data found!"
}
Attributes of Package.json
- name - name of the package
- version - version of the package
- description - description of the package
- homepage - homepage of the package
- author - author of the package
- contributors - name of the contributors to the package
- dependencies - list of dependencies. npm automatically installs all the dependencies mentioned here in the node_module folder of the package.
- repository - repository type and url of the package
- main - entry point of the package
- keywords - keywords
Uninstalling a module
Use following command to uninstall a Node.js module.
$ npm uninstall express
Once npm uninstall the package, you can verify by looking at the content of /node_modules/ directory or type the following command:
$ npm ls
Updating a module
Update package.json and change the version of the dependency which to be updated and run the following command.
$ npm update express
Search a module
Search package name using npm.
$ npm search express
Create a module
Creation of module requires package.json to be generated. Let's generate package.json using npm, which will generate basic skeleton of the package.json.
$ npm init This utility will walk you through creating a package.json file. It only covers the most common items, and tries to guess sane defaults. See 'npm help json' for definitive documentation on these fields and exactly what they do. Use 'npm install --save' afterwards to install a package and save it as a dependency in the package.json file. Press ^C at any time to quit. name: (webmaster)
You will need to provide all the required information about your module. YOu can take help from the above mentioned package.json file to understand the meanings of various information demanded. Once package.json is generated. Use the following command to register yourself with npm repository site using a valid email address.
$ npm adduser Username: mcmohd Password: Email: (this IS public) [email protected]
Now its time to publish your module:
$ npm publish
If everything is fine with your module, then it will be published in the reporsitory and will be accessible to install using npm like any other other Node.js module.