NPM 是随同 NodeJS 一起安装的包管理工具，可以解决 NodeJS 代码部署上的很多问题，常见的使用场景有以下几种：
- 允许我们从 NPM 服务器下载第三方编写的包到本地使用。
- 允许我们从 NPM 服务器下载并安装第三方编写的命令行程序到本地使用。
- 允许我们将自己编写的包或命令行程序上传到 NPM 服务器供他人使用。
新版的 nodejs 已经集成了 npm ，所以 npm 不需要单独安装。
1 淘宝 NPM 镜像
因为国内直接使用 npm 的官方镜像非常慢，所以推荐使用淘宝 NPM 镜像。这是一个完整 npmjs.org 镜像，我们可以用此代替官方版本(只读)，同步频率目前为 10分钟 一次，保证与官方服务同步。
安装指令：
npm install -g cnpm --registry=http://registry.npm.taobao.org
也可以用此指令，更新淘宝 NPM 镜像包。
安装成功后，就可以使用 cnpm 命令来安装模块了：
cnpm install [name]
淘宝 NPM 镜像完整说明：http://npm.taobao.org/
2 安装模块
npm 安装 Node.js 模块语法格式如下：
npm install
比如想安装 request 模块，就可以这样：
npm install request
不过还是建议用 cnpm 指令来安装模块，会更快些。
然后就可以通过 require 调用我们刚刚安装的模块。在 WebStorm 中，会弹出提示，让我们把模块写到 package.json 文件中。
通过 Alt + Shift + Enter 指令，就可以自动创建 package.json 文件并添加好对应的模块：
{
"name": "deniro-nodejs",
"version": "1.0.0",
"dependencies": {
"request": "latest"
}
}
3 全局安装与本地安装
npm 的包安装分为本地安装（local）、全局安装（global）两种，全局安装命令比本地安装命令，多了一个 -g。
cnpm install request # 本地安装
cnpm install request -g #全局安装
二者区别如下：
| 安装包路径 | 调用方式 | |
|---|---|---|
| 本地安装 | 放在 ./node_modules 下（运行 npm 命令时所在的目录），如果没有 node_modules 目录，会在当前执行 npm 命令的目录下生成 node_modules 目录。 | 通过 require() 来引入本地安装的包。 |
| 全局安装 | 放在 /usr/local 下或者 node.js 的安装目录。 | 可以直接在命令行里使用。 |
全局安装 request 模块时，会输出如下内容：
[1/20] aws-sign2@~0.7.0 installed at node_modules\[email protected]@aws-sign2
[2/20] aws4@^1.8.0 installed at node_modules\[email protected]@aws4
[3/20] caseless@~0.12.0 installed at node_modules\[email protected]@caseless
[4/20] is-typedarray@~1.0.0 installed at node_modules\[email protected]@is-typedarray
[5/20] forever-agent@~0.6.1 installed at node_modules\[email protected]@forever-agent
[6/20] isstream@~0.1.2 installed at node_modules\[email protected]@isstream
[7/20] oauth-sign@~0.9.0 installed at node_modules\[email protected]@oauth-sign
[8/20] performance-now@^2.1.0 installed at node_modules\[email protected]@performance-now
[9/20] json-stringify-safe@~5.0.1 installed at node_modules\[email protected]@json-stringify-safe
[10/20] combined-stream@~1.0.6 installed at node_modules\[email protected]@combined-stream
[11/20] form-data@~2.3.2 installed at node_modules\[email protected]@form-data
[12/20] extend@~3.0.2 installed at node_modules\[email protected]@extend
[13/20] qs@~6.5.2 installed at node_modules\[email protected]@qs
[14/20] mime-types@~2.1.19 installed at node_modules\[email protected]@mime-types
[15/20] safe-buffer@^5.1.2 installed at node_modules\[email protected]@safe-buffer
[16/20] tunnel-agent@^0.6.0 installed at node_modules\[email protected]@tunnel-agent
[17/20] uuid@^3.3.2 installed at node_modules\[email protected]@uuid
[18/20] tough-cookie@~2.5.0 installed at node_modules\[email protected]@tough-cookie
[19/20] har-validator@~5.1.3 installed at node_modules\[email protected]@har-validator
[20/20] http-signature@~1.2.0 installed at node_modules\[email protected]@http-signature
All packages installed (47 packages installed from npm registry, used 1s(network 1s), speed 857.68kB/s, json 46(93.67kB), tarball 968.13kB)
4 常用指令
（1）查看所有全局安装的模块
npm list -g
输出形如：
| | | +-- [email protected] deduped
| | | +-- [email protected] deduped
| | | `-- [email protected] deduped
| | +-- [email protected]
| | | +-- [email protected] deduped
| | | +-- [email protected] deduped
| | | +-- [email protected] deduped
| | | +-- [email protected] deduped
...
（2）查看某个模块的版本号
npm list [name]
输出形如：
[email protected] F:\WebstormProjects\deniro-nodejs
`-- [email protected]
输出格式为：projectName@projectVersion /path/to/project/folder。
（3）更新模块指令
npm update [name]
（4）搜索模块指令
npm search [name]
比如搜索 request 模块，会输出以下内容：
NAME | DESCRIPTION | AUTHOR | DATE | VERSION | KEYWORDS
superagent | elegant & feature… | =defunctzombie… | 2020-02-17 | 5.2.2 | agent ajax ajax api async await axios cancel client frisbee got http http h
tt
request-promise | The simplified HTTP… | =analog-nico… | 2019-11-04 | 4.2.5 | xhr http https promise request then thenable bluebird
request-promise-native | The simplified HTTP… | =analog-nico… | 2019-11-04 | 1.0.8 | xhr http https promise request then thenable native
needle | The leanest and… | =tomas | 2020-04-03 | 2.4.1 | http https simple request client multipart upload proxy deflate timeout char
s
request-progress | Tracks the download… | =satazor | 2016-12-01 | 3.0.0 | progress request mikeal size bytes percent percentage speed eta etr
supertest | SuperAgent driven… | =defunctzombie… | 2019-03-15 | 4.0.2 | superagent request tdd bdd http test testing
got | Human-friendly and… | =sindresorhus… | 2020-03-24 | 10.7.0 | http https http2 get got url uri request simple curl wget fetch net network
e
graphql-request | [![CircleCI](https:… | =schickling… | 2018-08-10 | 1.8.2 | graphql request fetch graphql-client apollo
morgan | HTTP request logger… | =dougwilson | 2020-03-20 | 1.10.0 | express http logger middleware
axios-mock-adapter | Axios adapter that… | =ctimmerm | 2020-03-22 | 1.18.1 | axios test mock request stub adapter
cookie-parser | Parse HTTP request… | =defunctzombie… | 2020-03-15 | 1.4.5 | cookie middleware
raf | requestAnimationFra… | =chrisdickinson… | 2018-11-02 | 3.4.1 | requestAnimationFrame polyfill
request-promise-core | Core Promise… | =analog-nico | 2019-11-03 | 1.1.3 | xhr http https promise request then thenable core
popsicle | Advanced HTTP… | =blakeembrey | 2019-11-03 | 12.0.5 | request http middleware node ajax browser promise
sync-request | Make synchronous… | =forbeslindesay | 2019-03-17 | 6.1.0 | request http https cache browserify synchronous sync
http-signature | Reference… | =arekinath… | 2020-04-02 | 1.3.4 | https request
cacheable-request | Wrap native HTTP… | =lukechilds | 2020-01-21 | 7.0.1 | HTTP HTTPS cache caching layer cacheable RFC 7234 RFC 7234 compliant
light-my-request | Fake HTTP injection… | =delvedor… | 2020-03-26 | 3.7.4 | http inject fake request server
proxy-addr | Determine address… | =dougwilson | 2020-02-24 | 2.0.6 | ip proxy x-forwarded-for
make-fetch-happen | Opinionated,… | =ruyadorno… | 2020-03-12 | 8.0.4 | http request fetch mean girls caching cache subresource integrity
（5）查看 npm 版本号
npm -v
5 package.json
package.json 位于模块包的根目录下（模块安装成功后，会放在 node_modules 下），用于定义模块包的属性。比如，request 模块的 package.json 配置如下：
{
"name": "request",
"description": "Simplified HTTP request client.",
"keywords": [
"http",
"simple",
"util",
"utility"
],
"version": "2.88.2",
"author": "Mikeal Rogers ",
"repository": {
"type": "git",
"url": "https://github.com/request/request.git"
},
"bugs": {
"url": "http://github.com/request/request/issues"
},
"license": "Apache-2.0",
"engines": {
"node": ">= 6"
},
"main": "index.js",
"files": [
"lib/",
"index.js",
"request.js"
],
"dependencies": {
"aws-sign2": "~0.7.0",
"aws4": "^1.8.0",
"caseless": "~0.12.0",
"combined-stream": "~1.0.6",
"extend": "~3.0.2",
"forever-agent": "~0.6.1",
"form-data": "~2.3.2",
"har-validator": "~5.1.3",
"http-signature": "~1.2.0",
"is-typedarray": "~1.0.0",
"isstream": "~0.1.2",
"json-stringify-safe": "~5.0.1",
"mime-types": "~2.1.19",
"oauth-sign": "~0.9.0",
"performance-now": "^2.1.0",
"qs": "~6.5.2",
"safe-buffer": "^5.1.2",
"tough-cookie": "~2.5.0",
"tunnel-agent": "^0.6.0",
"uuid": "^3.3.2"
},
"scripts": {
"test": "npm run lint && npm run test-ci && npm run test-browser",
"test-ci": "taper tests/test-*.js",
"test-cov": "nyc --reporter=lcov tape tests/test-*.js",
"test-browser": "node tests/browser/start.js",
"lint": "standard"
},
"devDependencies": {
"bluebird": "^3.2.1",
"browserify": "^13.0.1",
"browserify-istanbul": "^2.0.0",
"buffer-equal": "^1.0.0",
"codecov": "^3.0.4",
"coveralls": "^3.0.2",
"function-bind": "^1.0.2",
"karma": "^3.0.0",
"karma-browserify": "^5.0.1",
"karma-cli": "^1.0.0",
"karma-coverage": "^1.0.0",
"karma-phantomjs-launcher": "^1.0.0",
"karma-tap": "^3.0.1",
"nyc": "^14.1.1",
"phantomjs-prebuilt": "^2.1.3",
"rimraf": "^2.2.8",
"server-destroy": "^1.0.1",
"standard": "^9.0.0",
"tape": "^4.6.0",
"taper": "^0.5.0"
},
"greenkeeper": {
"ignore": [
"hawk",
"har-validator"
]
},
"__npminstall_done": "Sat Apr 18 2020 10:38:30 GMT+0800 (GMT+08:00)",
"_from": "[email protected]",
"_resolved": "https://registry.npm.taobao.org/request/download/request-2.88.2.tgz?cache=0&sync_timestamp=1581439349114&other_urls=https%3A%2F%2Fregistry.npm.taobao.org%2Frequest%2Fdownload%2Frequest-2.88.2.tgz"
}
具体属性说明如下：
| 属性 | 说明 |
|---|---|
| name | 包名。 |
| version | 包的版本号。 |
| description | 描述。 |
| homepage | 官网主页 url 。 |
| author | 作者姓名。 |
| contributors | 贡献者姓名。 |
| dependencies | 依赖包列表。如果依赖包没有安装，npm 会自动将依赖包安装在 node_module 目录下。 |
| repository | 包代码托管类型，可以是 git 或 svn，git 可在 Github 上。 |
| main | 指定了程序的主入口文件，require('moduleName') 就会加载这个文件。这个字段的默认值是模块根目录下面的 index.js。 |
| keywords | 关键字 |
6 创建模块
我们所开发的项目，其实本质上也是模块，因此也是通过 npm 进行管理的。
我们可以使用 NPM 生成 package.json 文件，生成的文件包含了这个项目的一些基本的内容。
创建模块指令为：npm init，执行过程中会以交互的方式，让我们输入包名、版本号、描述、入口文件、测试命令、git 仓库地址、关键字、作者、许可证等信息。必填项会提供默认值，我们可以修改这些默认值。
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 ` afterwards to install a package and
save it as a dependency in the package.json file.
Press ^C at any time to quit.
package name: (deniro-nodejs)
version: (1.0.0)
description: study node.js
entry point: (create_app.js) index.js
test command: make test
git repository:
keywords:
author: Deniro Lee
license: (ISC)
About to write to F:\WebstormProjects\deniro-nodejs\package.json:
{
"name": "deniro-nodejs",
"version": "1.0.0",
"dependencies": {
"request": "latest"
},
"description": "study node.js",
"main": "index.js",
"devDependencies": {},
"scripts": {
"test": "make test"
},
"author": "Deniro Lee",
"license": "ISC"
}
Is this OK? (yes) yes
执行后，就会在 package.json 中，加入以上这些配置项：
{
"name": "deniro-nodejs",
"version": "1.0.0",
"dependencies": {
"request": "latest"
},
"description": "study node.js",
"main": "index.js",
"devDependencies": {},
"scripts": {
"test": "make test"
},
"author": "Deniro Lee",
"license": "ISC"
}
7 版本号
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。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。
- 如果只是修复 bug ，需要更新 Z 位；
- 如果是新增了功能，但是向下兼容，需要更新 Y 位；
- 如果有大变动，向下不兼容，需要更新 X 位。