由于新版的nodejs已经集成了npm，所以之前npm也一并安装好了。同样可以通过输入 "npm -v" 来测试是否成功安装。命令如下，出现版本提示表示安装成功:由于新版的nodejs已经集成了npm，所以之前npm也一并安装好了。同样可以通过输入 "npm -v" 来测试是否成功安装。命令如下，出现版本提示表示安装成功:
| $ npm -v |
| 2.3.0 |
| $ sudo npm install npm -g |
| /usr/local/bin/npm -> /usr/local/lib/node_modules/npm/bin/npm-cli.js |
| npm@2.14.2 /usr/local/lib/node_modules/npm |
| npm install npm -g |
npm 安装 Node.js 模块语法格式如下：
| $ npm install <Module Name> |
| $ npm install express |
| var express = require('express'); |
npm 的包安装分为本地安装（local）、全局安装（global）两种，从敲的命令行来看，差别只是有没有-g而已，比如
| npm install express # 本地安装 |
| npm install express -g # 全局安装 |
| npm err! Error: connect ECONNREFUSED 127.0.0.1:8087 |
| $ npm config set proxy null |
如果你希望具备两者功能，则需要在两个地方安装它或使用 npm link。
接下来我们使用全局方式安装 express
| $ npm install express -g |
| express@4.13.3 node_modules/express |
| ├── escape-html@1.0.2 |
| ├── range-parser@1.0.2 |
| ├── merge-descriptors@1.0.0 |
| ├── array-flatten@1.1.1 |
| ├── cookie@0.1.3 |
| ├── utils-merge@1.0.0 |
| ├── parseurl@1.3.0 |
| ├── cookie-signature@1.0.6 |
| ├── methods@1.1.1 |
| ├── fresh@0.3.0 |
| ├── vary@1.0.1 |
| ├── path-to-regexp@0.1.7 |
| ├── content-type@1.0.1 |
| ├── etag@1.7.0 |
| ├── serve-static@1.10.0 |
| ├── content-disposition@0.5.0 |
| ├── depd@1.0.1 |
| ├── qs@4.0.0 |
| ├── finalhandler@0.4.0 (unpipe@1.0.0) |
| ├── on-finished@2.3.0 (ee-first@1.1.1) |
| ├── proxy-addr@1.0.8 (forwarded@0.1.0, ipaddr.js@1.0.1) |
| ├── debug@2.2.0 (ms@0.7.1) |
| ├── type-is@1.6.8 (media-typer@0.3.0, mime-types@2.1.6) |
| ├── accepts@1.2.12 (negotiator@0.5.3, mime-types@2.1.6) |
| └── send@0.13.0 (destroy@1.0.3, statuses@1.2.1, ms@0.7.1, mime@1.3.4, http-errors@1.3.1) |
| $ npm ls -g |
package.json 位于模块的目录下，用于定义包的属性。接下来让我们来看下 express 包的 package.json 文件，位于 node_modules/express/package.json 内容：
| { |
| "name": "express", |
| "description": "Fast, unopinionated, minimalist web framework", |
| "version": "4.13.3", |
| "author": { |
| "name": "TJ Holowaychuk", |
| "email": "tj@vision-media.ca" |
| }, |
| "contributors": [ |
| { |
| "name": "Aaron Heckmann", |
| "email": "aaron.heckmann+github@gmail.com" |
| }, |
| { |
| "name": "Ciaran Jessup", |
| "email": "ciaranj@gmail.com" |
| }, |
| { |
| "name": "Douglas Christopher Wilson", |
| "email": "doug@somethingdoug.com" |
| }, |
| { |
| "name": "Guillermo Rauch", |
| "email": "rauchg@gmail.com" |
| }, |
| { |
| "name": "Jonathan Ong", |
| "email": "me@jongleberry.com" |
| }, |
| { |
| "name": "Roman Shtylman", |
| "email": "shtylman+expressjs@gmail.com" |
| }, |
| { |
| "name": "Young Jae Sim", |
| "email": "hanul@hanul.me" |
| } |
| ], |
| "license": "MIT", |
| "repository": { |
| "type": "git", |
| "url": "git+https://github.com/strongloop/express.git" |
| }, |
| "homepage": "http://expressjs.com/", |
| "keywords": [ |
| "express", |
| "framework", |
| "sinatra", |
| "web", |
| "rest", |
| "restful", |
| "router", |
| "app", |
| "api" |
| ], |
| "dependencies": { |
| "accepts": "~1.2.12", |
| "array-flatten": "1.1.1", |
| "content-disposition": "0.5.0", |
| "content-type": "~1.0.1", |
| "cookie": "0.1.3", |
| "cookie-signature": "1.0.6", |
| "debug": "~2.2.0", |
| "depd": "~1.0.1", |
| "escape-html": "1.0.2", |
| "etag": "~1.7.0", |
| "finalhandler": "0.4.0", |
| "fresh": "0.3.0", |
| "merge-descriptors": "1.0.0", |
| "methods": "~1.1.1", |
| "on-finished": "~2.3.0", |
| "parseurl": "~1.3.0", |
| "path-to-regexp": "0.1.7", |
| "proxy-addr": "~1.0.8", |
| "qs": "4.0.0", |
| "range-parser": "~1.0.2", |
| "send": "0.13.0", |
| "serve-static": "~1.10.0", |
| "type-is": "~1.6.6", |
| "utils-merge": "1.0.0", |
| "vary": "~1.0.1" |
| }, |
| "devDependencies": { |
| "after": "0.8.1", |
| "ejs": "2.3.3", |
| "istanbul": "0.3.17", |
| "marked": "0.3.5", |
| "mocha": "2.2.5", |
| "should": "7.0.2", |
| "supertest": "1.0.1", |
| "body-parser": "~1.13.3", |
| "connect-redis": "~2.4.1", |
| "cookie-parser": "~1.3.5", |
| "cookie-session": "~1.2.0", |
| "express-session": "~1.11.3", |
| "jade": "~1.11.0", |
| "method-override": "~2.3.5", |
| "morgan": "~1.6.1", |
| "multiparty": "~4.1.2", |
| "vhost": "~3.0.1" |
| }, |
| "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-ci": "istanbul cover node_modules/mocha/bin/_mocha --report lcovonly -- --require test/support/env --reporter spec --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/" |
| }, |
| "gitHead": "ef7ad681b245fba023843ce94f6bcb8e275bbb8e", |
| "bugs": { |
| "url": "https://github.com/strongloop/express/issues" |
| }, |
| "_id": "express@4.13.3", |
| "_shasum": "ddb2f1fb4502bf33598d2b032b037960ca6c80a3", |
| "_from": "express@*", |
| "_npmVersion": "1.4.28", |
| "_npmUser": { |
| "name": "dougwilson", |
| "email": "doug@somethingdoug.com" |
| }, |
| "maintainers": [ |
| { |
| "name": "tjholowaychuk", |
| "email": "tj@vision-media.ca" |
| }, |
| { |
| "name": "jongleberry", |
| "email": "jonathanrichardong@gmail.com" |
| }, |
| { |
| "name": "dougwilson", |
| "email": "doug@somethingdoug.com" |
| }, |
| { |
| "name": "rfeng", |
| "email": "enjoyjava@gmail.com" |
| }, |
| { |
| "name": "aredridel", |
| "email": "aredridel@dinhe.net" |
| }, |
| { |
| "name": "strongloop", |
| "email": "callback@strongloop.com" |
| }, |
| { |
| "name": "defunctzombie", |
| "email": "shtylman@gmail.com" |
| } |
| ], |
| "dist": { |
| "shasum": "ddb2f1fb4502bf33598d2b032b037960ca6c80a3", |
| "tarball": "http://registry.npmjs.org/express/-/express-4.13.3.tgz" |
| }, |
| "directories": {}, |
| "_resolved": "https://registry.npmjs.org/express/-/express-4.13.3.tgz", |
| "readme": "ERROR: No README data found!" |
| } |
我们可以使用以下命令来卸载 Node.js 模块。
| $ npm uninstall express |
| $ npm ls |
更新模块
我们可以使用以下命令更新模块：
| $ npm update express |
使用以下来搜索模块：
| $ npm search express |
创建模块，package.json 文件是必不可少的。我们可以使用 NPM 生成 package.json 文件，生成的文件包含了基本的结果。
| $ npm init |
| This utility will walk you through creating a package.json file. |
| It only covers the most common items, and tries to guess sensible defaults. |
| See `npm help json` for definitive documentation on these fields |
| and exactly what they do. |
| Use `npm install <pkg> --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: (node_modules) web3 # 模块名 |
| version: (1.0.0) |
| description: Node.js 测试模块(www.web3.xin) # 描述 |
| entry point: (index.js) |
| test command: make test |
| git repository: https://github.com/web3/web3.git # Github 地址 |
| keywords: |
| author: |
| license: (ISC) |
| About to write to ……/node_modules/package.json: # 生成地址 |
| { |
| "name": "web3", |
| "version": "1.0.0", |
| "description": "Node.js 测试模块(www.web3.xin)", |
| …… |
| } |
| Is this ok? (yes) yes |
以上的信息，你需要根据你自己的情况输入。在最后输入 "yes" 后会生成 package.json 文件。
接下来我们可以使用以下命令在 npm 资源库中注册用户（使用邮箱注册）：
| $ npm adduser |
| Username: mcmohd |
| Password: |
| Email: (this IS public) mcmohd@gmail.com |
接下来我们就用以下命令来发布模块：
| $ npm publish |
如果你以上的步骤都操作正确，你就可以跟其他模块一样使用 npm 来安装。
使用NPM下载和发布代码时都会接触到版本号。NPM使用语义版本号来管理代码，这里简单介绍一下。
语义版本号分为X.Y.Z三位，分别代表主版本号、次版本号和补丁版本号。当代码变更时，版本号按以下原则更新。
版本号有了这个保证后，在申明第三方包依赖时，除了可依赖于一个固定版本号外，还可依赖于某个范围的版本号。例如"argv": "0.0.x"表示依赖于0.0.x系列的最新版argv。
NPM支持的所有版本号范围指定方式可以查看官方文档。
除了本章介绍的部分外，NPM还提供了很多功能，package.json里也有很多其它有用的字段。
除了可以在npmjs.org/doc/查看官方文档外，这里再介绍一些NPM常用命令。
NPM提供了很多命令，例如install和publish，使用npm help可查看所有命令。
NPM提供了很多命令，例如install和publish，使用npm help可查看所有命令。
使用npm help <command>可查看某条命令的详细帮助，例如npm help install。
在package.json所在目录下使用npm install . -g可先在本地安装当前命令行程序，可用于发布前的本地测试。
使用npm update <package>可以把当前目录下node_modules子目录里边的对应模块更新至最新版本。
使用npm update <package> -g可以把全局安装的对应命令行程序更新至最新版。
使用npm cache clear可以清空NPM本地缓存，用于对付使用相同版本号发布新版本代码的人。
使用npm unpublish <package>@<version>可以撤销发布自己发布过的某个版本代码。
