kbone 高级 - 环境判断

柔情只为你懂 2022-12-04 08:50 140阅读 0赞

### 1、用法 ###

对于开发者来说，可能需要针对不同端做一些特殊的逻辑，因此也就需要一个方法来判断区分不同的环境。kbone 推荐的做法是通过 webpack 注入一个环境变量：

// webpack.mp.config.js
    module.exports = {
      plugins: [
        new webpack.DefinePlugin({
          'process.env.isMiniprogram': true,
        }),
        // ... other options
      ],
      // ... other options
    }

后续在业务代码中，就可以通过 process.env.isMiniprogram 来判断是否在小程序环境：

if (process.env.isMiniprogram) {
      console.log('in miniprogram')
    } else {
      console.log('in web')
    }

### 2、案例 ###

在 `kbone-advanced` 目录下创建 `01-env` 目录，本案例在这个目录下完成。

### 2.1 创建 package.json ###

cd 01-env
    npm init -y

编辑 package.json：

{
      "name": "01-env",
      "version": "1.0.0",
      "description": "",
      "main": "index.js",
      "scripts": {
        "build": "rimraf dist/web && cross-env NODE_ENV=production webpack --config build/webpack.config.js --progress --hide-modules",
        "mp": "cross-env NODE_ENV=production webpack --config build/webpack.mp.config.js --progress --hide-modules"
      },
      "dependencies": {
        "add": "^2.0.6",
        "vue": "^2.5.11"
      },
      "browserslist": [
        "> 1%",
        "last 2 versions",
        "not ie <= 8"
      ],
      "devDependencies": {
        "babel-core": "^6.26.0",
        "babel-loader": "^7.1.2",
        "babel-preset-env": "^1.6.0",
        "cross-env": "^5.0.5",
        "css-loader": "^0.28.7",
        "file-loader": "^1.1.4",
        "html-webpack-plugin": "^4.0.0-beta.5",
        "mini-css-extract-plugin": "^0.5.0",
        "optimize-css-assets-webpack-plugin": "^5.0.1",
        "stylehacks": "^4.0.3",
        "vue-loader": "^15.7.0",
        "vue-template-compiler": "^2.6.10",
        "webpack": "^4.29.6",
        "webpack-cli": "^3.2.3",
        "mp-webpack-plugin": "latest"
      },
      "keywords": [],
      "author": "",
      "license": "ISC"
    }

安装依赖包：

npm install

### 2.2 配置 webpack ###

在 01-env/build 目录下创建 webpack.config.js，内容如下：

var path = require('path')
    var MiniCssExtractPlugin = require('mini-css-extract-plugin')
    const { VueLoaderPlugin } = require('vue-loader')
    const HtmlWebpackPlugin = require('html-webpack-plugin')
    
    module.exports = {
      mode: 'production',
      entry: {
        index: path.resolve(__dirname, '../src/main.js'),
      },
      output: {
        path: path.resolve(__dirname, '../dist/web/'),
        publicPath: './',
        filename: '[name].js'
      },
      target: 'web',
      module: {
        rules: [
          {
            test: /\.css$/,
            use: [
              MiniCssExtractPlugin.loader,
              'css-loader'
            ],
          },      {
            test: /\.vue$/,
            loader: 'vue-loader',
          },
          {
            test: /\.js$/,
            use: {
              loader: 'babel-loader',
              options: {
                presets: ['env']
              }
            },
            exclude: /node_modules/
          },
          {
            test: /\.(png|jpg|gif|svg)$/,
            loader: 'file-loader',
            options: {
              name: '[name].[ext]?[hash]'
            }
          }
        ]
      },
    
      resolve: {
        extensions: ['*', '.js', '.vue', '.json']
      },
    
      plugins: [
        new MiniCssExtractPlugin({
          filename: '[name].css'
        }),
        new VueLoaderPlugin(),
        new HtmlWebpackPlugin({
          filename: 'index.html',
          chunks: ['index'],
          template: path.join(__dirname, '../index.html')
        }),
      ]
    }

### 2.3 创建 main.js ###

在 `01-env/src` 目录下创建 `main.js`，内容如下：

import Vue from 'vue'
    import App from './App'
    
    new Vue({
      el: '#app',
      render: h => h(App)
    })

### 2.3 创建 App.vue ###

在 `01-env/src` 目录下创建 `App.vue`，内容如下：

<template>
      <div>
        I am {
       {info}}
      </div>
    </template>
    
    <script>
    export default {
      computed: {
        info() {
          if (process.env.isMiniprogram) {
            return 'in miniprogram'
          } else {
            return 'in web'
          }
        }
      }
    }
    </script>

### 2.4 编写入口文件 index.html ###

在项目根目录下创建 `index.html`，内容如下：

<!DOCTYPE html>
    <html lang="en">
      <head>
        <meta charset="utf-8">
        <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no,minimal-ui, viewport-fit=cover" />
        <meta content="yes"name="apple-mobile-web-app-capable"/>
        <meta content="black"name="apple-mobile-web-app-status-bar-style"/>
        <meta name="format-detection"content="telephone=no, email=no" />
        <title>vue</title>
        <style type="text/css">
          #app {
            font-family: 'Avenir', Helvetica, Arial, sans-serif;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            text-align: center;
            color: #2c3e50;
            margin-top: 60px;
          }
        </style>
      </head>
      <body>
        <div id="app"></div>
      </body>
    </html>

### 2.5 Web端效果预览 ###

npm run web

![format_png][]

### 2.6 创建 webpack.mp.config.js ###

在 `01-env/build` 目录下创建 webpack.mp.config.js，内容如下：

const path = require('path')
    const webpack = require('webpack')
    const MiniCssExtractPlugin = require('mini-css-extract-plugin')
    const { VueLoaderPlugin } = require('vue-loader')
    const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
    const TerserPlugin = require('terser-webpack-plugin')
    const MpPlugin = require('mp-webpack-plugin') // 用于构建小程序代码的 webpack 插件
    
    const isOptimize = false // 是否压缩业务代码，开发者工具可能无法完美支持业务代码使用到的 es 特性，建议自己做代码压缩
    
    module.exports = {
      mode: 'production',
      entry: {
        'app': path.resolve(__dirname, '../src/main.mp.js')
      },
      output: {
        path: path.resolve(__dirname, '../dist/mp/common'), // 放到小程序代码目录中的 common 目录下
        filename: '[name].js', // 必需字段，不能修改
        library: 'createApp', // 必需字段，不能修改
        libraryExport: 'default', // 必需字段，不能修改
        libraryTarget: 'window', // 必需字段，不能修改
      },
      target: 'web', // 必需字段，不能修改
      optimization: {
        runtimeChunk: false, // 必需字段，不能修改
        splitChunks: { // 代码分隔配置，不建议修改
          chunks: 'all',
          minSize: 1000,
          maxSize: 0,
          minChunks: 1,
          maxAsyncRequests: 100,
          maxInitialRequests: 100,
          automaticNameDelimiter: '~',
          name: true,
          cacheGroups: {
            vendors: {
              test: /[\\/]node_modules[\\/]/,
              priority: -10
            },
            default: {
              minChunks: 2,
              priority: -20,
              reuseExistingChunk: true
            }
          }
        },
    
        minimizer: isOptimize ? [
          // 压缩CSS
          new OptimizeCSSAssetsPlugin({
            assetNameRegExp: /\.(css|wxss)$/g,
            cssProcessor: require('cssnano'),
            cssProcessorPluginOptions: {
              preset: ['default', {
                discardComments: {
                  removeAll: true,
                },
                minifySelectors: false, // 因为 wxss 编译器不支持 .some>:first-child 这样格式的代码，所以暂时禁掉这个
              }],
            },
            canPrint: false
          }),
          // 压缩 js
          new TerserPlugin({
            test: /\.js(\?.*)?$/i,
            parallel: true,
          })
        ] : [],
      },
      module: {
        rules: [
          {
            test: /\.css$/,
            use: [
              MiniCssExtractPlugin.loader,
              'css-loader'
            ],
          },
          {
            test: /\.vue$/,
            loader: [
              'vue-loader',
            ],
          },
          {
            test: /\.js$/,
            use: {
              loader: 'babel-loader',
              options: {
                presets: ['env']
              }
            },
            exclude: /node_modules/
          },
          {
            test: /\.(png|jpg|gif|svg)$/,
            loader: 'file-loader',
            options: {
              name: '[name].[ext]?[hash]'
            }
          }
        ]
      },
    
      resolve: {
        extensions: ['*', '.js', '.vue', '.json']
      },
    
      plugins: [
        new webpack.DefinePlugin({
          'process.env.isMiniprogram': true, // 注入环境变量，用于业务代码判断
        }),
        new MiniCssExtractPlugin({
          filename: '[name].wxss',
        }),
        new VueLoaderPlugin(),
        new MpPlugin(require('./miniprogram.config.js')),
      ],
    }

### 2.7 创建 main.mp.js ###

在 `01-env/src` 下创建 `main.mp.js` 文件，内容如下：

import Vue from 'vue'
    import App from './App'
    
    export default function createApp() {
      const container = document.createElement('div')
      container.id = 'app'
      document.body.appendChild(container)
    
      return new Vue({
        el: '#app',
        render: h => h(App)
      })
    }

### 2.8 小程序端效果预览 ###

npm run mp

![format_png 1][]

[format_png]: /images/20221123/d56db92b58ff492cb19411540b92a65c.png
[format_png 1]: /images/20221123/32134b94640f4e9ba38481f239477760.png