kbone 高级 - 环境判断
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 install2.2 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：
I am {{info}}
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：
vue
2.5 Web端效果预览
npm run web
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