01 . Vue简介,原理,环境安装

简介

vue是一个JavaMVVM库，是一套用于构建用户界面的渐进式框架，是初创项目的首选前端框架。它是以数据驱动和组件化的思想构建的，采用自底向上增量开发的设计。它是轻量级的，它有很多独立的功能或库，我们会根据我们的项目来选用vue的一些功能。它提供了更加简洁、更易于理解的API，使得我们能够快速地上手并使用Vue.js.

安装vue

Vue环境安装

运行vue等技术开发的客户端项目,需要安装Node.js环境

Node下载

可以到nodejs的下载页面: http://nodejs.cn/download/下载对应的安装包

1.Windows电脑安装Nodejs环境

• 1、windows环境下选择.msi安装文件。然后进行双击node.msi，选择安装路径。
• 2、配置环境变量。在计算机（或者我的电脑）右击属性 -> 高级系统设置 -> 环境变量进行配置。新建NODE_PATH变量并设置Nodejs的安装目录。

macOS系统安装Nodejs

在终端中使用brew命令安装nodejs。详细命令：

brew install nodejs

Linux系统安装Nodejs

在nodejs的下载页面选择linux类别下的64位文件，下载文件为tar.xz格式的压缩文件。然后依次执行解压缩和建立软连接的命令：

tar -xvf   node-v10.15.3-linux-x64.tar.xz
vi /etc/profile
export NODEJS=/opt/node/node-v10.15.3-linux-x64
export PATH=$NODEJS/bin:$PATH

// 保存/etc/profile文件后
node -v
// 看版本

安装脚手架工具vue-cli

/*
		npm install --global vue-cli
*/

安装webpack

/*
		npm install -g webpack
		vue init webpack myVue

		npm install -g webpack
/Users/youmen/.nvm/versions/node/v10.14.2/bin/webpack -> /Users/youmen/.nvm/versions/node/v10.14.2/lib/node_modules/webpack/bin/webpack.js
+ webpack@5.4.0
added 82 packages from 122 contributors in 6.878s
\W $ vue init webpack myvue  

? Project name helloworld
? Project description student vue demo1
? Author youmen@163.com
? Vue build standalone
? Install vue-router? Yes
? Use ESLint to lint your code? No
? Set up unit tests Yes
? Pick a test runner jest
? Setup e2e tests with Nightwatch? No
? Should we run `npm install` for you after the project has
been created? (recommended) npm

		安装中有个选项(Use ESLint to line your code? 选择No)

		进入myVue,使用npm install 安装package.json中的依赖
		cd myVue
		npm install

		运行项目
		npm run dev
*/

安装nvm

管理node版本,非必须

// mac
git clone https://github.com/nvm-sh/nvm.git
cd nvm
./install.sh

cat ~/.bash_profile
export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh" # This loads nvm

// 换源
export NVM_NODEJS_ORG_MIRROR=http://npm.taobao.org/mirrors/node
export NVM_IOJS_ORG_MIRROR=http://npm.taobao.org/mirrors/iojs

source ~/.bash_profile
nvm --version
0.37.0

// 安装指定版本
nvm install 10.14.2

安装yarn

包管理工具

brew install yarn

安装vue cli

npm config set registry https://registry.npm.taobao.org/
npm install -g @vue/cli

yarn global add @vue/cli

创建vue项目

vue create ginessentail-vue
Vue CLI v4.5.8
? Please pick a preset: (Use arrow keys)
  Default ([Vue 2] babel, eslint)
  Default (Vue 3 Preview) ([Vue 3] babel, eslint)
❯  Manually select features 

Vue CLI v4.5.8
? Please pick a preset: Manually select features
? Check the features needed for your project:
 ◉ Choose Vue version
 ◉ Babel
 ◯ TypeScript
 ◯ Progressive Web App (PWA) Support
 ◉ Router
 ◉ Vuex
❯◯ CSS Pre-processors
 ◉ Linter / Formatter
 ◯ Unit Testing
 ◯ E2E Testing

Vue CLI v4.5.8
? Please pick a preset: Manually select features
? Check the features needed for your project: Choose Vue version, Babel, Router, Vuex, Lin
ter
? Choose a version of Vue.js that you want to start the project with 2.x
? Use history mode for router? (Requires proper server setup for index fallback in product
ion) (Y/n) y

Vue CLI v4.5.8
? Please pick a preset: Manually select features
? Check the features needed for your project: Choose Vue version, Babel, Router, Vuex, CSS
 Pre-processors, Linter
? Choose a version of Vue.js that you want to start the project with 3.x (Preview)
? Use history mode for router? (Requires proper server setup for index fallback in product
ion) Yes
? Pick a CSS pre-processor (PostCSS, Autoprefixer and CSS Modules are supported by default
):
  Sass/SCSS (with dart-sass)
❯ Sass/SCSS (with node-sass)
  Less
  Stylus 

Vue CLI v4.5.8
? Please pick a preset: Manually select features
? Check the features needed for your project: Choose Vue version, Babel, Router, Vuex, CSS
 Pre-processors, Linter
? Choose a version of Vue.js that you want to start the project with 3.x (Preview)
? Use history mode for router? (Requires proper server setup for index fallback in product
ion) Yes
? Pick a CSS pre-processor (PostCSS, Autoprefixer and CSS Modules are supported by default
): Sass/SCSS (with node-sass)
? Pick a linter / formatter config:
  ESLint with error prevention only
❯ ESLint + Airbnb config
  ESLint + Standard config
  ESLint + Prettier 

Vue CLI v4.5.8
? Please pick a preset: Manually select features
? Check the features needed for your project: Choose Vue version, Babel, Router, Vuex, CSS
 Pre-processors, Linter
? Choose a version of Vue.js that you want to start the project with 3.x (Preview)
? Use history mode for router? (Requires proper server setup for index fallback in product
ion) Yes
? Pick a CSS pre-processor (PostCSS, Autoprefixer and CSS Modules are supported by default
): Sass/SCSS (with node-sass)
? Pick a linter / formatter config: Airbnb
? Pick additional lint features: Lint on save
? Where do you prefer placing config for Babel, ESLint, etc.? (Use arrow keys)
❯ In dedicated config files
  In package.json 

success Saved lockfile.
  Done in 17.00s.
  Invoking generators...
  Installing additional dependencies...

yarn install v1.22.10
[1/4]   Resolving packages...
[2/4]   Fetching packages...
[3/4]   Linking dependencies...
[4/4]   Building fresh packages...
success Saved lockfile.
  Done in 8.86s.
  Running completion hooks...

  Generating README.md...

  Successfully created project ginessentail-vue.
  Get started with the following commands:

 $ cd ginessentail-vue
 $ yarn serve

cd ginessentail-vue
yarn serve

引入bootstrap

yarn add vue bootstrap-vue bootstrap

项目目录说明

/*
		build：项目构建(webpack)相关代码
    config：配置目录，包括端口号等
    node_modules：npm加载的项目依赖块
    src：这里是我们要开发的目录，基本上要做的事情都在这个目录里。里面包含了几个目录及文件：
    assets: 放置一些图片，如logo等
    components：该目录里存放的我们的开发文件组件，主要的开发文件都存放在这里了
    App.vue：项目入口文件
    main.js：项目的核心文件
    router：路由配置目录
    static：放置一些静态资源文件
    test：初始测试目录，可删除
    .xxxx文件：这些是一些配置文件，包括语法配置，git配置等
    index.html：首页入口文件
    package.json：项目配置文件
    README.md：项目的说明文档，markdown 格式
*/

Vue项目启动流程

1.找到package.json文件

/*
		在执行npm run dev的时候，会去在当前文件夹下的项目中找package.json文件,启动开发服务器，默认端口是8080;
*/

2.找到src的main.json文件,在该文件中new Vue实例,要加载的模板内容App

3.App是src目录下的App.vue结尾的文件

4.在App.vue所对应的模板当中，有一个router-view在src目录下有一个router文件夹，该文件夹有个index.js文件，该文件是配置路由词典，指定了路由地址是空，加载HelloWorld组件

vue运行是基于node环境的,,构建vue框架之前,需要确保node环境安装成功

vue生命周期示意图