Nodejs understand articles

Modular commonJS

Introduction

JS is mainly to develop the back end of the performance, commonJS is a specification, nodejs and webpack is a concrete realization of commonJS

Other modular specifications: seajs.js / require.js CMD / AMD / UMD es5

effect

The variables have file scope, do not pollute the global variable

System Module

http fs querystring url

Entry

require('模块名')
require('模块名').xx  按需引用

Do not specify a path: go first system modules -> then find node_modules from the project environment | bower_components (dependent on module) -> not found

Specify the path: to find the specified path -> not found

Support any type

Export

exports.自定义属性 = 值 | any

Batch Export all properties

Can output multiple times

module.exports = 值 | any		

Only output once, output many times, if desired, can be integrated into a given target output

note

commonJS is nodejs default management module does not support modular management es6, but supports all es6 + syntax

NPM

The following only a brief introduction. For in-depth understanding of NPM can refer to this article, NPM's common commands .

effect

Help you install the module (package), automatically install dependencies, package management (add, delete, update, all package items)

Similar: Bower the Yarn

Installed in the global environment

• Installed into the computer system environment
• Can be used in any position to use
• The global installed usually: command-line tools, scaffolding

npm install 包名  简写（npm i 包名 -g	）		     安装
npm uninstall 包名  简写（npm uninstall 包名 -g）     卸载

Installation to the project environment

Use only in the current directory, you need to run on behalf of npm

Initialize the project environment

npm init   在项目包中引导创建一个package.json 文件

Npm management initialization file package.json

package-lock.json dependent files used to cure

{
  "name": "npm",	//项目名称
  "version": "0.0.1",	//版本
  "description": "test and play",	//描述
  "main": "index.js", //入口文件
  "dependencies": {  //项目依赖  上线也要用
    "jquery": "^3.2.1"
  },
  "devDependencies": { //开发依赖 上线就不用
    "animate.css": "^3.5.2"
  },
  "scripts": {	//命令行
    "test": "命令行",
  },
  "repository": {	//仓库信息
    "type": "git",
    "url": "git+https://github.com/alexwa9.github.io/2017-8-28.git"
  },
  "keywords": [  //关键词
    "test",'xx','oo'
  ],
  "author": "wan9",
  "license": "ISC",	//认证
  "bugs": {
    "url": "https://github.com/alexwa9.github.io/2017-8-28/issues"  //问题提交
  },
  "homepage": "https://github.com/alexwa9.github.io/2017-8-28#readme"  //首页
}

Project Dependencies

Only be used in the current project, on the line need to rely on this --save

//安装
npm i 包名 --save
npm install 包名 -S
npm install 包名@x.x.x -S

//卸载
npm uninstall 包名 --save
npm uninstall 包名 -S

Development dependence

Only be used in the current project, on the line, do not need to rely on the --save-dev

npm install 包名 --save-dev
npm install 包名 -D

View package

npm list  列出所有已装包
npm outdated 版本对比(安装过得包)
npm info 包名 查看当前包概要信息 
npm view 包名 versions 查看包历史版本列表

And install any dependencies

npm install 

All the packages installed inside the specified package.json

Version constraint

^x.x.x   约束主版本，后续找最新
~x.x.x   保持前两位不变，后续找最新
*		 安装最新版本
x.x.x 	 指定一个版本

Select source

npm install nrm -g     安装选择源的工具包
nrm ls  			   查看所有源
nrm test 			   测试所有源
nrm use				   切换源名

Suddenly installation card

ctrl + c -> npm uninstall 包名  -> npm cache 清除缓存 -> 换4g网络 -> npm install 包名

Release package

• Official website registration
• log in
  • npm login log in
  • Enter user / password / email
• Creating a Package
  • npm init -y
  • Creating entrance index.js
  • Write, output
• release
  • npm publish
• Iteration
  • Revision number
  • npm publish
• delete
  • npm unpublish

Package release, iteration, delete, needs to be in the package directory

Delete packages sometimes need to send a message

Spread

peerDependencies release dependent
optionalDependencies optional dependency
bundledDependencies bundled rely
contributors to contribute to your packing people. Contributors are a group of people.
files contained in the project file. You can specify individual files or entire directories using wildcards to include files that meet specific criteria

YARN

Official website

installation

Quguan network installation

Baidu network disk installation package
link: https://pan.baidu.com/s/1UmeUhduxGLrWrQMWOv_pog
extraction code: 27ml

Note: Do not npm i yarn -g with yarn is easy to install, but should go to the official website to download the archive to ensure hard write to the registry and environment variables, global post-installation package by yarn convenience

use

Initialize a new project

yarn init  

Add dependencies

yarn add [ 包名 ]
yarn add [ 包名 ]@[version]
yarn add [ 包名 ]@[tag]

Add good yarn.lock it will automatically generate a file dependencies later, similar package.json as to help us record downloaded package.
Note :
If this project uses yarn to install the package, do not back the project in other environments such as npm download package, because more or less will be some conflict.

The dependency to different dependencies category

They were added to the dependencies, devDependencies, peerDependenciesand optionalDependenciescategories:

yarn add [ 包名 ] --save   | -S 
yarn add [ 包名 ] --dev    | -D 
yarn add [ 包名 ] --peer
yarn add [ 包名 ] --optional

Upgrade dependencies

yarn upgrade [ 包名 ]
yarn upgrade [ 包名 ]@[version]
yarn upgrade [ 包名 ]@[tag]

Removing dependencies

yarn remove [ 包名 ]

All rely installation project

yarn

or

yarn install

Installed in the global

yarn global add [ 包名 ]				//global的位置测试不能变
yarn global remove [ 包名 ]

BOWER

Official website

Installation bower

npm install -g bower

Installation package to the global environment

bower i 包名 -g		     安装
bower uninstall 包名 -g	 卸载

Installation package to the project environment

Initialize the project environment

bower init

bower.json third-party package management profiles

Project Dependencies

Only be used in the current project, on the line, this also needs to rely on --save

//安装
同npm
bower install 包名#x.x.x -S 指定版本使用#

//卸载
同npm

Development dependence

Only be used in the current project, on the line, do not need to rely on the --save-dev

同npm

Entry

require('模块名')
require('模块名').xx  按需引用

Do not specify a path: go first system modules -> then find node_modules from the project environment | bower_components (dependent on module) -> not found

Specify the path: to find the specified path -> not found

Support any type

Export

exports.自定义属性 = 值 | any

Batch Export all properties

Can output multiple times

module.exports = 值 | any		

Output only once

note

commonJS is nodejs default management module does not support modular management es6, but supports all es6 + syntax

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