微信小程序如何在浏览器运行
首先，小程序原生代码是比较难运行在浏览器端的，想要通过这个思路实现的朋友可以试试wept，但是wept已经不更新了。查阅了一些资料后，最终采用的思路是：小程序使用mpvue开发（一个类vue框架），而mpvue工程转化为vue工程并适配到浏览器。
那么，接下来的问题是：
- 如何将mpvue工程打包为vue工程
- 打包成vue工程后，需要做哪些适配
如何将mpvue工程打包为vue工程
针对第一个问题，主要思路编写mpvue打包成vue工程的webpack配置即可，期间参考了一下网上的资料总算搞定了。在开始编写配置文件前，首先确认mpvue版本，打开工程根目录package.json，节选如下：
"dependencies": {
"axios": "^0.18.0",
"mpvue": "^1.0.11",
"mpvue-wxparse": "^0.6.5",
"vue": "^2.5.16",
"vue-router": "^3.0.1",
"vuex": "^3.0.1"
},
mpvue新版本的打包配置和旧版有微妙的区别，本文选择的是1.0.11版本。
接下来，大致分为如下几步：
- 添加buildH5配置
- 添加configH5配置
- 代码入口适配
- 添加编译命令
添加buildH5配置
标准mpvue工程在根目录下都会有一个build目录。现在为了生成vue工程，需要新建一个buildH5目录。该目录下需要添加如下文件，这些配置几乎和项目没什么关系，不用改动：
build.js
require('./check-versions')()
process.env.NODE_ENV = 'production'
var ora = require('ora')
var rm = require('rimraf')
var path = require('path')
var chalk = require('chalk')
var webpack = require('webpack')
var config = require('../configH5')
var webpackConfig = require('./webpack.prod.conf')
var spinner = ora('building for production...')
spinner.start()
rm(path.join(config.build.assetsRoot, config.build.assetsSubDirectory), err => {
if (err) throw err
webpack(webpackConfig, (err, stats) => {
spinner.stop()
if (err) throw err
process.stdout.write(stats.toString({
colors: true,
modules: false,
children: false, // If you are using ts-loader, setting this to true will make TypeScript errors show up during build.
chunks: false,
chunkModules: false
}) + '\n\n')
if (stats.hasErrors()) {
console.log(chalk.red(' Build failed with errors.\n'))
process.exit(1)
}
console.log(chalk.cyan(' Build complete.\n'))
console.log(chalk.yellow(
' Tip: built files are meant to be served over an HTTP server.\n' +
' Opening index.html over file:// won\'t work.\n'
))
})
})
check-versions.js
'use strict'
const chalk = require('chalk')
const semver = require('semver')
const packageConfig = require('../package.json')
const shell = require('shelljs')
function exec (cmd) {
return require('child_process').execSync(cmd).toString().trim()
}
const versionRequirements = [
{
name: 'node',
currentVersion: semver.clean(process.version),
versionRequirement: packageConfig.engines.node
}
]
if (shell.which('npm')) {
versionRequirements.push({
name: 'npm',
currentVersion: exec('npm --version'),
versionRequirement: packageConfig.engines.npm
})
}
module.exports = function () {
const warnings = []
for (let i = 0; i < versionRequirements.length; i++) {
const mod = versionRequirements[i]
if (!semver.satisfies(mod.currentVersion, mod.versionRequirement)) {
warnings.push(mod.name + ': ' +
chalk.red(mod.currentVersion) + ' should be ' +
chalk.green(mod.versionRequirement)
)
}
}
if (warnings.length) {
console.log('')
console.log(chalk.yellow('To use this template, you must update following to modules:'))
console.log()
for (let i = 0; i < warnings.length; i++) {
const warning = warnings[i]
console.log(' ' + warning)
}
console.log()
process.exit(1)
}
}
dev-client.js
/* eslint-disable */
require('eventsource-polyfill')
var hotClient = require('webpack-hot-middleware/client?noInfo=true&reload=true')
hotClient.subscribe(function (event) {
if (event.action === 'reload') {
window.location.reload()
}
})
utils.js
'use strict'
const path = require('path')
const config = require('../configH5')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const packageConfig = require('../package.json')
exports.assetsPath = function (_path) {
const assetsSubDirectory = process.env.NODE_ENV === 'production'
? config.build.assetsSubDirectory
: config.dev.assetsSubDirectory
return path.posix.join(assetsSubDirectory, _path)
}
exports.cssLoaders = function (options) {
// console.log(options || {}, options)
options = options || {}
// console.log('generateLoaders', options.usePostCSS)
const cssLoader = {
loader: 'css-loader',
options: {
sourceMap: options.sourceMap
}
}
const postcssLoader = {
loader: 'postcss-loader',
options: {
sourceMap: options.sourceMap
}
}
// generate loader string to be used with extract text plugin
function generateLoaders (loader, loaderOptions) {
const loaders = options.usePostCSS ? [cssLoader, postcssLoader] : [cssLoader]
// , postcssLoader
if (loader) {
loaders.push({
loader: loader + '-loader',
options: Object.assign({}, loaderOptions, {
sourceMap: options.sourceMap
})
})
}
// Extract CSS when that option is specified
// (which is the case during production build)
if (options.extract) {
return ExtractTextPlugin.extract({
use: loaders,
fallback: 'vue-style-loader'
})
} else {
return ['vue-style-loader'].concat(loaders)
}
}
// https://vue-loader.vuejs.org/en/configurations/extract-css.html
return {
css: generateLoaders(),
postcss: generateLoaders(),
less: generateLoaders('less'),
sass: generateLoaders('sass', { indentedSyntax: true }),
scss: generateLoaders('sass'),
stylus: generateLoaders('stylus'),
styl: generateLoaders('stylus')
}
}
// Generate loaders for standalone style files (outside of .vue)
exports.styleLoaders = function (options) {
const output = []
const loaders = exports.cssLoaders(options)
for (const extension in loaders) {
const loader = loaders[extension]
output.push({
test: new RegExp('\\.' + extension + '$'),
use: loader
})
}
return output
}
exports.createNotifierCallback = () => {
const notifier = require('node-notifier')
return (severity, errors) => {
if (severity !== 'error') return
const error = errors[0]
const filename = error.file && error.file.split('!').pop()
notifier.notify({
title: packageConfig.name,
message: severity + ': ' + error.name,
subtitle: filename || '',
icon: path.join(__dirname, 'logo.png')
})
}
}
vue-loader.conf.js
'use strict'
const utils = require('./utils')
const config = require('../configH5')
const isProduction = process.env.NODE_ENV === 'production'
const sourceMapEnabled = isProduction
? config.build.productionSourceMap
: config.dev.cssSourceMap
module.exports = {
loaders: utils.cssLoaders({
sourceMap: sourceMapEnabled,
extract: isProduction
}),
cssSourceMap: sourceMapEnabled,
cacheBusting: config.dev.cacheBusting,
transformToRequire: {
video: ['src', 'poster'],
source: 'src',
img: 'src',
image: 'xlink:href'
}
}
webpack.base.conf.js
'use strict'
const path = require('path')
const utils = require('./utils')
const config = require('../configH5')
const vueLoaderConfig = require('./vue-loader.conf')
function resolve (dir) {
return path.join(__dirname, '..', dir)
}
const createLintingRule = () => ({
test: /\.(js|vue)$/,
loader: 'eslint-loader',
enforce: 'pre',
include: [resolve('src'), resolve('test')],
options: {
formatter: require('eslint-friendly-formatter'),
emitWarning: !config.dev.showEslintErrorsInOverlay
}
})
module.exports = {
context: path.resolve(__dirname, '../'),
entry: {
app: './src/mainH5.js'
// app: './module/' + enterdir + '/src/main.js'
},
output: {
path: config.build.assetsRoot,
filename: '[name].js',
publicPath: process.env.NODE_ENV === 'production'
? '.' + config.build.assetsPublicPath
: config.dev.assetsPublicPath
},
resolve: {
extensions: ['.js', '.vue', '.json', '.html'],
alias: {
'vue$': 'vue/dist/vue.esm.js',
'@': resolve('src'),
'pages': resolve('src/pages'),
'packageA': resolve('src/pages/packageA'),
'packageB': resolve('src/pages/packageB'),
}
},
module: {
rules: [
...(config.dev.useEslint ? [createLintingRule()] : []),
{
test: /\.vue$/,
loader: 'vue-loader',
options: vueLoaderConfig
},
{
test: /\.js$/,
loader: 'babel-loader',
include: [resolve('src'), resolve('test'), resolve('node_modules/webpack-dev-server/client')]
},
{
test: /\.css$/,
use: [
'vue-style-loader',
'px2rpx-loader',
'css-loader'
],
},
{
test: /\.less$/,
loader: "style-loader!css-loader!less-loader",
},
{
test: /\.(png|jpe?g|gif|svg)(\?.*)?$/,
loader: 'url-loader',
options: {
limit: 1000,
name: utils.assetsPath('img/[name].[ext]?v=[hash:7]')
}
},
{
test: /\.(mp4|webm|ogg|mp3|wav|flac|aac)(\?.*)?$/,
loader: 'url-loader',
options: {
limit: 1000,
name: utils.assetsPath('media/[name].[ext]?v=[hash:7]')
}
},
{
test: /\.(woff2?|eot|ttf|otf)(\?.*)?$/,
loader: 'url-loader',
options: {
limit: 10000,
name: utils.assetsPath('fonts/[name].[ext]?v=[hash:7]')
}
}
]
},
node: {
// prevent webpack from injecting useless setImmediate polyfill because Vue
// source contains it (although only uses it if it's native).
setImmediate: false,
// prevent webpack from injecting mocks to Node native modules
// that does not make sense for the client
dgram: 'empty',
fs: 'empty',
net: 'empty',
tls: 'empty',
child_process: 'empty'
}
}
webpack.dev.conf.js
'use strict'
const utils = require('./utils')
const webpack = require('webpack')
const config = require('../configH5')
const merge = require('webpack-merge')
const path = require('path')
const baseWebpackConfig = require('./webpack.base.conf')
const CopyWebpackPlugin = require('copy-webpack-plugin')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const FriendlyErrorsPlugin = require('friendly-errors-webpack-plugin')
const portfinder = require('portfinder')
const HOST = process.env.HOST
const PORT = process.env.PORT && Number(process.env.PORT)
const devWebpackConfig = merge(baseWebpackConfig, {
module: {
rules: utils.styleLoaders({ sourceMap: config.dev.cssSourceMap, usePostCSS: false})
},
// cheap-module-eval-source-map is faster for development
devtool: config.dev.devtool,
// these devServer options should be customized in /config/index.js
devServer: {
clientLogLevel: 'warning',
historyApiFallback: {
rewrites: [
{ from: /.*/, to: path.posix.join(config.dev.assetsPublicPath, 'index.html') },
],
},
hot: true,
contentBase: false, // since we use CopyWebpackPlugin.
compress: true,
host: HOST || config.dev.host,
port: PORT || config.dev.port,
open: config.dev.autoOpenBrowser,
overlay: config.dev.errorOverlay
? { warnings: false, errors: true }
: false,
publicPath: config.dev.assetsPublicPath,
proxy: config.dev.proxyTable,
quiet: true, // necessary for FriendlyErrorsPlugin
watchOptions: {
poll: config.dev.poll,
}
},
plugins: [
new webpack.DefinePlugin({
'process.env': require('../configH5/dev.env')
}),
new webpack.HotModuleReplacementPlugin(),
new webpack.NamedModulesPlugin(), // HMR shows correct file names in console on update.
new webpack.NoEmitOnErrorsPlugin(),
// https://github.com/ampedandwired/html-webpack-plugin
new HtmlWebpackPlugin({
filename: 'index.html',
template: 'index.html',
inject: true
}),
// copy custom static assets
new CopyWebpackPlugin([
{
from: path.resolve(__dirname, '../static'),
to: config.dev.assetsSubDirectory,
ignore: ['.*']
}
]),
new CopyWebpackPlugin([
{
from: path.resolve(__dirname, '../src/app.json'),
to: config.dev.assetsSubDirectory + '/../app.json',
ignore: ['.*']
}
]),
new CopyWebpackPlugin([
{
from: path.resolve(__dirname, '../project.config.json'),
to: config.dev.assetsSubDirectory + '/../project.config.json',
ignore: ['.*']
}
])
]
})
module.exports = new Promise((resolve, reject) => {
portfinder.basePort = process.env.PORT || config.dev.port
portfinder.getPort((err, port) => {
if (err) {
reject(err)
} else {
// publish the new Port, necessary for e2e tests
process.env.PORT = port
// add port to devServer config
devWebpackConfig.devServer.port = port
// Add FriendlyErrorsPlugin
devWebpackConfig.plugins.push(new FriendlyErrorsPlugin({
compilationSuccessInfo: {
messages: [`Your application is running here: http://${devWebpackConfig.devServer.host}:${port}`],
},
onErrors: config.dev.notifyOnErrors
? utils.createNotifierCallback()
: undefined
}))
resolve(devWebpackConfig)
}
})
})
webpack.prod.conf.js
'use strict'
const path = require('path')
const utils = require('./utils')
const webpack = require('webpack')
const config = require('../configH5/index')
const merge = require('webpack-merge')
const baseWebpackConfig = require('./webpack.base.conf')
const CopyWebpackPlugin = require('copy-webpack-plugin')
const HtmlWebpackPlugin = require('html-webpack-plugin')
const ExtractTextPlugin = require('extract-text-webpack-plugin')
const OptimizeCSSPlugin = require('optimize-css-assets-webpack-plugin')
const UglifyJsPlugin = require('uglifyjs-webpack-plugin')
const env = process.env.NODE_ENV === 'testing'
? require('../configH5/test.env')
: require('../configH5/prod.env')
const webpackConfig = merge(baseWebpackConfig, {
module: {
rules: utils.styleLoaders({
sourceMap: config.build.productionSourceMap,
extract: false,
usePostCSS: false
})
},
devtool: config.build.productionSourceMap ? config.build.devtool : false,
output: {
path: config.build.assetsRoot,
filename: utils.assetsPath('js/[name].js?v=[chunkhash]'),
chunkFilename: utils.assetsPath('js/[id].js?v=[chunkhash]')
},
plugins: [
// http://vuejs.github.io/vue-loader/en/workflow/production.html
new webpack.DefinePlugin({
'process.env': env
}),
new UglifyJsPlugin({
uglifyOptions: {
compress: {
warnings: false
}
},
sourceMap: true,
parallel: true
}),
// extract css into its own file
//
new ExtractTextPlugin({
filename: utils.assetsPath('css/[name].css?v=[contenthash]'),
// Setting the following option to `false` will not extract CSS from codesplit chunks.
// Their CSS will instead be inserted dynamically with style-loader when the codesplit chunk has been loaded by webpack.
// It's currently set to `true` because we are seeing that sourcemaps are included in the codesplit bundle as well when it's `false`,
// increasing file size: https://github.com/vuejs-templates/webpack/issues/1110
allChunks: true,
}),
// Compress extracted CSS. We are using this plugin so that possible
// duplicated CSS from different components can be deduped.
new OptimizeCSSPlugin({
cssProcessorOptions: config.build.productionSourceMap
? { safe: true, map: { inline: false } }
: { safe: true }
}),
// generate dist index.html with correct asset hash for caching.
// you can customize output by editing /index.html
// see https://github.com/ampedandwired/html-webpack-plugin
new HtmlWebpackPlugin({
filename: config.build.index,
template: 'index.html',
inject: true,
minify: false,
// minify: {
// removeComments: true,
// collapseWhitespace: true,
// removeAttributeQuotes: true
// // more options:
// // https://github.com/kangax/html-minifier#options-quick-reference
// },
// necessary to consistently work with multiple chunks via CommonsChunkPlugin
chunksSortMode: 'dependency'
}),
// keep module.id stable when vendor modules does not change
new webpack.HashedModuleIdsPlugin(),
// enable scope hoisting
new webpack.optimize.ModuleConcatenationPlugin(),
// split vendor js into its own file
new webpack.optimize.CommonsChunkPlugin({
name: 'vendor',
minChunks (module) {
// any required modules inside node_modules are extracted to vendor
return (
module.resource &&
/\.js$/.test(module.resource) &&
module.resource.indexOf(
path.join(__dirname, '../node_modules')
) === 0
)
}
}),
// extract webpack runtime and module manifest to its own file in order to
// prevent vendor hash from being updated whenever app bundle is updated
new webpack.optimize.CommonsChunkPlugin({
name: 'manifest',
minChunks: Infinity
}),
// This instance extracts shared chunks from code splitted chunks and bundles them
// in a separate chunk, similar to the vendor chunk
// see: https://webpack.js.org/plugins/commons-chunk-plugin/#extra-async-commons-chunk
new webpack.optimize.CommonsChunkPlugin({
name: 'app',
async: 'vendor-async',
children: true,
minChunks: 3
}),
// copy custom static assets
new CopyWebpackPlugin([
{
from: path.resolve(__dirname, '../static'),
to: config.build.assetsSubDirectory,
ignore: ['.*']
}
]),
new CopyWebpackPlugin([
{
from: path.resolve(__dirname, '../src/app.json'),
to: config.dev.assetsSubDirectory + '/../app.json',
ignore: ['.*']
}
]),
new CopyWebpackPlugin([
{
from: path.resolve(__dirname, '../project.config.json'),
to: config.dev.assetsSubDirectory + '/../project.config.json',
ignore: ['.*']
}
])
]
})
if (config.build.productionGzip) {
const CompressionWebpackPlugin = require('compression-webpack-plugin')
webpackConfig.plugins.push(
new CompressionWebpackPlugin({
asset: '[path].gz[query]',
algorithm: 'gzip',
test: new RegExp(
'\\.(' +
config.build.productionGzipExtensions.join('|') +
')$'
),
threshold: 10240,
minRatio: 0.8
})
)
}
if (config.build.bundleAnalyzerReport) {
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin
webpackConfig.plugins.push(new BundleAnalyzerPlugin())
}
module.exports = webpackConfig
需要注意的是，webpack.base.conf.js中用了诸如px2rpx-loader、vue-style-loader，如果没有安装会提示报错，照着报错安装下就好了。
添加configH5配置
同样地，在工程根目录下新建configH5目录，目录下需要添加几个文件。
dev.env.js
var merge = require('webpack-merge')
var prodEnv = require('./prod.env')
module.exports = merge(prodEnv, {
NODE_ENV: '"development"'
})
prod.env.js
module.exports = {
NODE_ENV: '"production"'
}
index.js
'use strict'
// Template version: 1.3.1
// see http://vuejs-templates.github.io/webpack for documentation.
const path = require('path')
module.exports = {
dev: {
// Paths
assetsSubDirectory: 'static',
assetsPublicPath: '/',
proxyTable: {},
// Various Dev Server settings
host: 'localhost', // can be overwritten by process.env.HOST
port: 8080, // can be overwritten by process.env.PORT, if port is in use, a free one will be determined
autoOpenBrowser: false,
errorOverlay: true,
notifyOnErrors: true,
poll: false, // https://webpack.js.org/configuration/dev-server/#devserver-watchoptions-
// Use Eslint Loader?
// If true, your code will be linted during bundling and
// linting errors and warnings will be shown in the console.
useEslint: false,
// If true, eslint errors and warnings will also be shown in the error overlay
// in the browser.
showEslintErrorsInOverlay: false,
/**
* Source Maps
*/
// https://webpack.js.org/configuration/devtool/#development
devtool: 'cheap-module-eval-source-map',
// If you have problems debugging vue-files in devtools,
// set this to false - it *may* help
// https://vue-loader.vuejs.org/en/options.html#cachebusting
cacheBusting: true,
cssSourceMap: true
},
build: {
// Template for index.html
index: path.resolve(__dirname, '../distH5/index.html'),
// Paths
assetsRoot: path.resolve(__dirname, '../distH5'),
assetsSubDirectory: 'static',
assetsPublicPath: '/',
/**
* Source Maps
*/
productionSourceMap: false,
// https://webpack.js.org/configuration/devtool/#production
devtool: '#source-map',
// Gzip off by default as many popular static hosts such as
// Surge or Netlify already gzip all static assets for you.
// Before setting to `true`, make sure to:
// npm install --save-dev compression-webpack-plugin
productionGzip: false,
productionGzipExtensions: ['js', 'css'],
// Run the build command with an extra argument to
// View the bundle analyzer report after build finishes:
// `npm run build --report`
// Set to `true` or `false` to always turn it on or off
bundleAnalyzerReport: process.env.npm_config_report
}
}
代码入口适配
细心看过上面那些配置文件的人应该已经发现，入口是这样配置的：
entry: {
app: './src/mainH5.js'
// app: './module/' + enterdir + '/src/main.js'
},
下面实现mainH5.js
import Vue from 'vue'
import App from './AppH5'
import router from './router'
import global from './utils/global.js'
import store from './store/index.js'
import {loginUtils} from './utils/LoginUtils'
// import '../static/fonts/icomoon.css'
// 试工程实际情况，这里可能有项目独特的配置，总之把main.js复制过来就好了
Vue.use(global);
Vue.prototype.$store = store;
Vue.config.productionTip = false;
Vue.prototype.$customEvent = new Vue(App);
App.mpType = 'app';
Vue.mixin(loginUtils)
Vue.prototype.$bus = new Vue()
Vue.config.productionTip = false
/* eslint-disable no-new */
let vue = new Vue({
el: '#app',
router,
components: { App },
template: '似乎和main.js没有太大区别？没有关系，稍后就有新建一个入口文件的必要了。这里的一个区别是：
import App from './AppH5'
引入的不是默认的App.vue呢。那么接下来新建AppH5.vue，放在mainH5.js同级目录下：
<template>
<div id="app">
<router-view></router-view>
</div>
</template>
<script>
export default {
name: 'App'
}
</script>
<style>
</style>
可以看到这里用了router。mpvue开发小程序大概率不会用router，因为有wx.navigateTo这种原生api，但是浏览器可不会识别wx api，因此路由需要由router实现。
在src下新建一个router目录，目录下新建一个index.js，在这个文件中，把所有页面注册：
import Vue from 'vue'
import Router from 'vue-router'
import main from '../pages/main/index'
import my from '../pages/my/index'
Vue.use(Router)
export default new Router({
routes: [
{
path: '/',
name: 'main',
component: main,
alias: '/pages/main/main'
},
{
path: '/pages/my/main',
name: 'my',
component: my
}
]
})
这里只是一个示例，实际项目要把所有页面写到这个配置中。
添加编译命令
就像npm run dev、npm run build一样，我们需要一个相似的命令生成vue工程。修改package.json，就像这样：
"scripts": {
"dev": "node build/dev-server.js",
"start": "node build/dev-server.js",
"build": "node build/build.js",
"devH5": "webpack-dev-server --iframe --progress --config buildH5/webpack.dev.conf.js",
"all": "npm run dev && npm run devH5",
"buildH5": "node buildH5/build.js"
},
现在可以用npm run devH5生成项目在webpack-dev-server上的预览，或用npm run buildH5生成vue工程了，只不过生成出来的东西暂时没法跑，应该全是报错吧（笑），接下来需要做一些适配工作。
小程序工程适配为vue工程
之前提到过，wx api在浏览器端不识别，这个显然需要适配。然而除了这个，小程序的生命周期、组件也是问题。
适配wx api
首先需要新建utils/wx.js，将所有用到的wx api封装起来：
getParams: function (target) {
return target.$route.query
},
redirectTo: function (url, target) {
let route = target.$router.matcher.match(url.url)
if (route) {
window.parent.onRedirectTo(route)
}
target.$router.replace(url.url)
},
switchTab: function (url, target) {
let route = target.$router.matcher.match(url.url)
if (route) {
window.parent.onSwitchTab(route)
}
target.$router.replace(url.url)
},
navigateBack: function (delta, target) {
let r = window.parent.onNavigateBack(delta)
target.$router.replace(r.path)
},
reLaunch: function (url, target) {
let route = target.$router.matcher.match(url.url)
if (route) {
window.parent.onRelaunch(route)
}
target.$router.replace(url.url)
},
getSystemInfoSync() {
return {
screenWidth: 750,
screenHeight: 1334,
windowWidth: 750,
windowHeight: 1334
}
},
这里只展示了部分wx api在浏览器端的实现，有需要的自行实现或适配。
注意getParams，在mpvue中，接收上一个页面传的query参数可以这么写：
mounted () {
let id = this.$root.$mp.query.id
}
但这种方式并不适用于vue，所以改为用router的方式获取参数，而页面组件中，调用封装的getParams方法即可。
适配生命周期
小程序中onLoad、onShow、onUnLoad等生命周期在vue里可是行不通的。当然，新项目可以通过开发上的约定，例如必须使用vue生命周期、不使用小程序生命周期来适配，而老项目一个个改就显得麻烦了。因此，这里的思路是在vue的runtime里加入小程序的生命周期，即定制。
这里需要修改node_modules/vue/dist/vue.esm.js：
var LIFECYCLE_HOOKS = [
'beforeCreate',
'created',
'onLoad', // 加入生命周期
'onShow', // 加入生命周期
'beforeMount',
'mounted',
'beforeUpdate',
'updated',
'beforeDestroy',
'onUnload', // 加入生命周期
'destroyed',
'activated',
'deactivated',
'errorCaptured'
];
还是这个文件，修改initMixin方法：
vm._self = vm;
initLifecycle(vm);
initEvents(vm);
initRender(vm);
callHook(vm, 'beforeCreate');
initInjections(vm); // resolve injections before data/props
initState(vm);
initProvide(vm); // resolve provide after data/props
callHook(vm, 'created');
callHook(vm, 'onLoad'); // 调起生命周期
callHook(vm, 'onShow'); // 调起生命周期
/* istanbul ignore if */
if (process.env.NODE_ENV !== 'production' && config.performance && mark) {
vm._name = formatComponentName(vm, false);
mark(endTag);
measure(("vue " + (vm._name) + " init"), startTag, endTag);
}
if (vm.$options.el) {
vm.$mount(vm.$options.el);
}
// 下略
找到Vue.prototype.$destroy，在代码里加入一行onUnload的调起：
Vue.prototype.$destroy = function () {
var vm = this;
if (vm._isBeingDestroyed) {
return
}
callHook(vm, 'beforeDestroy');
callHook(vm, 'onUnload'); // 调起生命周期
vm._isBeingDestroyed = true;
// remove self from parent
var parent = vm.$parent;
if (parent && !parent._isBeingDestroyed && !vm.$options.abstract) {
remove(parent.$children, vm);
}
// 下略
}
现在vue可以调起小程序的生命周期了。
适配组件
小程序原生开发了许多组件，这些组件作为html标签当然无法被浏览器识别，有些甚至和html冲突（例如小程序的input，在html里也有个同名的）。这里适配有相当的工作量，因为组件之多、组件的属性、方法之多是需要一个团队来完成的。然而，要达到预览效果的话，仅需要适配常用组件已经常用的属性就行了。
以小程序image标签为例。首先，在工程src下新建componentsH5目录，目录下新建wx-image.vue：
<template>
<div ref="img_loader" v-if="mode !== 'aspectFix'" style="display: flex; flex-direction: row; justify-content: center; align-items: center; overflow: hidden;">
<img :src="resolvedSrc" :calprop="resolveSize" :style="rStyle" />
</div>
<div ref="img_loader" v-else style="display: flex; flex-direction: column; justify-content: center; align-items: center; overflow: hidden;">
<img :src="resolvedSrc" :calprop="resolveSize" :style="rStyle" />
</div>
</template>
<script>
export default {
name: "wx-image",
props: {
src: {
type: String
},
mode: {
type: String
}
},
data () {
return {
rStyle: {}
}
},
computed: {
resolvedSrc () {
if (!this.src) {
return this.src
}
if (this.src.startsWith(('/static'))) {
return '.' + this.src
} else {
return this.src
}
},
resolveSize () {
if (!this.src) {
this.rStyle = {width: '100%', height: '100%'}
return
}
let self = this
let img = new Image()
img.src = self.src
let mode = self.mode
let imgWidth = img.width
let imgHeight = img.height
let resolvedWidth = imgWidth
let resolvedHeight = imgHeight
setTimeout(function () {
let border = self.$refs.img_loader.getBoundingClientRect()
let borderWidth = border.width
let borderHeight = border.height || imgHeight
if (borderHeight === 0 || imgHeight === 0) {
self.rStyle = {width: '100%', height: '100%'}
return
}
if (!mode) {
self.rStyle = {width: borderWidth + 'px', height: borderHeight + 'px'}
return
} else if (mode === 'scaleToFill') {
self.rStyle = {width: '100%', height: '100%'}
return
} else if (mode === 'aspectFit') {
console.log('aspectFit');
// 保持横纵比缩放，长边显示
if (borderWidth / borderHeight > imgWidth / imgHeight) {
resolvedWidth = imgWidth / imgHeight * borderHeight
resolvedHeight = borderHeight
console.log('aspectFit1', borderWidth, borderHeight, resolvedWidth, resolvedHeight);
} else {
resolvedWidth = borderWidth
resolvedHeight = borderWidth * imgHeight / imgWidth
console.log('aspectFit2', borderWidth, borderHeight, resolvedWidth, resolvedHeight);
}
} else if (mode === 'aspectFill') {
// 保持横纵比缩放，长边裁剪
if (borderWidth / borderHeight > imgWidth / imgHeight) {
resolvedWidth = borderWidth
resolvedHeight = borderWidth * imgHeight / imgWidth
} else {
resolvedWidth = imgWidth / imgHeight * borderHeight
resolvedHeight = borderHeight
}
} else if (mode === 'aspectFix') {
// 宽度不变，高度自适应
resolvedWidth = borderWidth
resolvedHeight = borderWidth * imgHeight / imgWidth
}
self.rStyle = {width: resolvedWidth + 'px', height: resolvedHeight + 'px'}
})
return {}
}
}
}
</script>
<style scoped>
</style>
在这里，适配了image两个最重要的属性：src和mode。注意，计算属性resolvedSrc将"/static"开头的传入值自动转化成了"./static"，这是因为生成的vue工程放在服务端并作为静态资源暴露的时候，写作"/static/*"格式的本地图片无法显示，所以适配成更兼容的格式。另一方面，mode对小程序中4大缩放模式做了简单的适配，保证显示效果。
那么，我们只要全局注册一个名为的image组件，其实现是wx-image.vue就好了！修改mainH5.js：
// 引入组件库
import wxImage from './componentsH5/wx-image'
// 全局mixin
Vue.mixin({
components: {
'image': wxImage
}
})
之前新建mainH5.js而不是直接用main.js的理由在此，我们需要在这里一一注册我们的适配组件。
但是很遗憾，这样无法通过vue的编译，查看vue源码发现，vue禁止image作为组件名：
export function validateComponentName (name: string) {
if (!/^[a-zA-Z][\w-]*$/.test(name)) {
warn(
'Invalid component name: "' + name + '". Component names ' +
'can only contain alphanumeric characters and the hyphen, ' +
'and must start with a letter.'
)
}
if (isBuiltInTag(name) || config.isReservedTag(name)) {
warn(
'Do not use built-in or reserved HTML elements as component ' +
'id: ' + name
)
}
}
这里方法1是修改vue源码，去掉这个限制，思路2是修改打包，将image标签自动转化为wx-image标签。这里选择的是方法2，找到node_modules/vue-template-compiler/build.js，搜索2403行左右的parseHTML，如下修改：
parseHTML(template, {
warn: warn$1,
expectHTML: options.expectHTML,
isUnaryTag: options.isUnaryTag,
canBeLeftOpenTag: options.canBeLeftOpenTag,
shouldDecodeNewlines: options.shouldDecodeNewlines,
shouldDecodeNewlinesForHref: options.shouldDecodeNewlinesForHref,
shouldKeepComment: options.comments,
start: function start (tag, attrs, unary) {
// check namespace.
// inherit parent ns if there is one
var ns = (currentParent && currentParent.ns) || platformGetTagNamespace(tag);
// 将微信小程序组件简单适配到h5
// 添加的代码
if (tag === 'view') {
tag = 'div'
}
if (tag === 'image') {
tag = 'wx-image'
}
// 添加的代码结束
// handle IE svg bug
/* istanbul ignore if */
if (isIE && ns === 'svg') {
attrs = guardIESVGBug(attrs);
}
// 下略
修改后，image标签就会被自动转化了。最后别忘了修改mainH5.js：
Vue.mixin({
components: {
wxImage // 修改这里
}
})
这样就完成了image标签的基本适配，其他组件用相似的思路就行了。
这里再举例一个scroll-view的简单适配：
<template>
<div :class="containerStyle">
<slot></slot>
</div>
</template>
<script>
export default {
name: "scroll-view",
props: {
scrollX: {
type: Boolean,
default: false
},
scrollY: {
type: Boolean,
default: false
}
},
computed: {
containerStyle () {
if (this.scrollX) {
return 'sv_x'
}
if (this.scrollY) {
return 'sv_y'
}
return ''
}
}
}
</script>
<style scoped>
.sv_x {
overflow-x: auto;
overflow-y: hidden;
display: flex;
flex-direction: row;
}
.sv_y {
overflow-x: hidden;
overflow-y: auto;
display: flex;
flex-direction: column;
flex-wrap: nowrap;
}
</style>
常见的组件如view、image、scroll-view、text、swiper等适配后，至少大部分布局显示是不成问题的。
适配单位
小程序一般使用rpx作为单位开发，而rpx在浏览器上无法识别。如何在尽可能不修改项目代码的同时做到适配呢？
一般来说，项目代码中用到rpx的有这么几种情况：
1 style内联
<div style="width: 750rpx; height: 50rpx;">div>
2 style内联（动态）
<div :style="{width: divWidth + diffWidth + 'rpx'}">div>
3 style标签中
<style>
.container {
width: 750rpx;
}
style>
4 代码中
let divStyle = {width: divWidth + diffWidth + 'rpx'}
首先，对于2、4情况，想要自动实现只能通过编写脚本进行文本替换，然而实际情况复杂，所以写脚本是吃力不讨好的，实际开发中尽量避免，如果用到这种动态情况，用vw这种兼容更强的单位就好。对于1、3情况，是有办法解决的。
修改node_modules/lib/loader.js：
processCss(content, map, {
mode: moduleMode ? "local" : "global",
from: loaderUtils.getRemainingRequest(this).split("!").pop(),
to: loaderUtils.getCurrentRequest(this).split("!").pop(),
query: query,
resolve: resolve,
minimize: this.minimize,
loaderContext: this,
sourceMap: sourceMap
}, function(err, result) {
if(err) return callback(err);
var cssAsString = JSON.stringify(result.source);
// 这里添加一行，替换rpx为px
cssAsString = cssAsString.replace(/rpx/g, 'px')
// for importing CSS
var importUrlPrefix = getImportPrefix(this, query);
// 下略
这样style标签中的rpx被自动转化了。我们只需要将预览窗口的宽度定为750px，即可达到适配目的。预览窗口本身可以scale缩放，来适应浏览器的窗口大小。
另外，对于情况1，我们可以写一个类似px2rpx-loader的插件来实现转换，但是更简单粗暴的方法是直接修改node_modules/px2rpx/bin/px2rpx.js，将其实现从"px->rpx"改为"rpx->px"：
#!/usr/bin/env node
var program = require('commander');
var pkg = require('../package.json');
var Px2rpx = require('../index');
var chalk = require('chalk');
var path = require('path');
var fs = require('fs-extra');
// string to variables of proper type（thanks to zepto）
function deserializeValue(value) {
var num;
try {
return value ?
value == "true" || value == true ||
(value == "false" || value == false ? false :
value == "null" ? null :
!/^0/.test(value) && !isNaN(num = Number(value)) ? num :
/^[\[\{]/.test(value) ? JSON.parse(value) :
value)
: value;
} catch (e) {
return value;
}
}
function saveFile(filePath, content) {
fs.createFileSync(filePath);
fs.writeFileSync(filePath, content, {encoding: 'utf8'});
console.log(chalk.green.bold('[Success]: ') + filePath);
}
program.version(pkg.version)
.option('-u, --rpxUnit [value]', 'set `rpx` unit value (default: 75)', 75)
.option('-x, --threeVersion [value]', 'whether to generate @1x, @2x and @3x version stylesheet (default: false)', false)
.option('-r, --rpxVersion [value]', 'whether to generate rpx version stylesheet (default: true)', true)
.option('-b, --baseDpr [value]', 'set base device pixel ratio (default: 2)', 2)
.option('-p, --rpxPrecision [value]', 'set rpx value precision (default: 6)', 6)
.option('-o, --output [path]', 'the output file dirname')
.parse(process.argv);
if (!program.args.length) {
console.log(chalk.yellow.bold('[Info]: ') + 'No files to process!');
return false;
}
var config = {
rpxUnit: deserializeValue(program.rpxUnit),
threeVersion: deserializeValue(program.threeVersion),
rpxVersion: deserializeValue(program.rpxVersion),
baseDpr: deserializeValue(program.baseDpr),
rpxPrecision: deserializeValue(program.rpxPrecision)
};
var px2rpxIns = new Px2rpx(config);
program.args.forEach(function (filePath) {
if (path.extname(filePath) !== '.css') {
return;
}
var cssText = fs.readFileSync(filePath, {encoding: 'utf8'});
var outputPath = program.output || path.dirname(filePath);
var fileName = path.basename(filePath);
// generate @1x, @2x and @3x version stylesheet
if (config.threeVersion) {
for (var dpr = 1; dpr <= 3; dpr++) {
var newCssText = px2rpxIns.generateThree(cssText, dpr);
var newFileName = fileName.replace(/(.debug)?.css/, dpr + 'x.debug.css');
var newFilepath = path.join(outputPath, newFileName);
saveFile(newFilepath, newCssText);
}
}
// generate rpx version stylesheet
if (config.rpxVersion) {
var newCssText = px2rpxIns.generaterpx(cssText);
var newFileName = fileName.replace(/(.debug)?.css/, '.debug.css');
var newFilepath = path.join(outputPath, newFileName);
saveFile(newFilepath, newCssText);
}
});
结束语
本文提供了一个小程序在浏览器端运行的思路，其中适配组件和api是工作量大的地方，但由于一些原因，我不会在Github放demo，想要真正商业级实现这个需求就看自身了。