详解Web使用webpack构建前端项目

前端之家收集整理的这篇文章主要介绍了详解Web使用webpack构建前端项目前端之家小编觉得挺不错的,现在分享给大家,也给大家做个参考。

好久没写技术博客了,原因在于最近在学习前端方面的技术,熟悉我的同学都知道,之前我有使用Vue搭建了一个个人简历,体验了一把最新的前端技术,但之前我们使用的是vue-cli脚手架工具,对于如何自己实现前端构建工具,当下最为流行的就是webpack和gulp了,之前一篇我们讲了gulp,这一篇我们来好好讨论webpack.

说起webpack,想必做前端的同学肯定不会陌生,其实之前我们使用gulp构建的时候,也使用了webpack的打包技术,其实gulp和webpack并不是相互替代的关系,而是相辅相成,今天我们就来好好看看webpack的神奇之处吧.

我们学习一样新技术,首先肯定是从他的官方文档入手,当然我们要学习也是学最新版的.webpack的官方教程写的非常好,一步一步讲的很到位,各位同学可以直接阅读官方文档,比起博客中的二手,三手以及四手的资料,官方文档肯定是你更好的选择.

这篇文章,不是教你什么看这一篇就够了之类的对于官方文档拷贝的水文,而是能让你快速上手并且觉得所谓的webpack其实也就这么一回事,webpack你只要记住一个中心思想,就和上面的图示一样,将所有错综复杂的文件逻辑打包压缩成几个静态资源,不多说了,我们还是看代码来的实际.

webpack.config.js

对于一些抛弃jquery迎接react和vue的前端开发者来说,webpack虽然可能自己没有写过,但看总是看过的吧,一般来说,都会有一个webpack.config.js的webpack配置文件.下面的代码就是一个简单的webpack的配置,麻雀虽小五脏俱全.

module.exports = { //导出 webpack固定写法
context: path.join(__dirname),devtool: debug ? "inline-sourcemap" : null,//是否使用map工具,用于浏览器debug
entry: "./src/js/root.js",//打包的实体
module: {
loaders: [ //加载的配置
{
test: /.js?$/,exclude: /(node_modules)/,loader: 'babel-loader',query: {
presets: ['react','es2015'],//添加预处理器
plugins: ['react-html-attrs'],//添加组件的插件配置
}
},{ test: /.css$/,loader: 'style-loader!css-loader' },{
test: /.less$/,loader: "style!css!less"
}
]
},output: { //输出的路径及文件
path: __dirname,filename: "./src/bundle.js"
},plugins: debug ? [] : [ //一些插件
new webpack.optimize.DedupePlugin(),new webpack.optimize.OccurenceOrderPlugin(),new webpack.optimize.UglifyJsPlugin({ mangle: false,sourcemap: false }),],};

webpack主要包括entry,module,output,plugins四大类,官方文档说的已经很清楚了,想要进一步的学习,请翻阅官方文档,如果不想折腾直接拷贝上述代码即可.

相较gulp,webpack在打包方面更为精简,这也是流行的原因吧,但光看上面的文件,的确也是简单,但是还有进一步改善的空间.

package.json

对于npm的介绍我就不多说了,我们直接来看文件.

css-loader": "^0.28.7","csv-loader": "^2.1.1","file-loader": "^0.11.2","html-webpack-plugin": "^2.30.1","json-loader": "^0.5.7","lodash": "^4.17.4","style-loader": "^0.18.2","uglifyjs-webpack-plugin": "^0.4.6","webpack": "^3.6.0","webpack-dev-middleware": "^1.12.0","webpack-dev-server": "^2.8.2","webpack-merge": "^4.1.0","xml-loader": "^1.2.1" },"dependencies": { //生产环境依赖 "babel-plugin-import": "^1.5.0","babel-plugin-react-html-attrs": "^2.0.0","babel-preset-es2015": "^6.24.1","babel-preset-react": "^6.24.1","babelify": "^7.3.0","react": "^15.6.1","react-dom": "^15.6.1","react-mixin": "^4.0.0","react-router": "^4.2.0" } }

命令行工具就是npm run build等于执行了webpack --config webpack.prod.js,而npm start 等于执行了webpack-dev-server --open --config webpack.dev.js.简单易懂吧.

在项目依赖中,哦们加了很多的插件和loader,都是用来搭建webpack的,官方文档的教程中都会讲到,值得注意的就是webpack-merge这个包,这个包可以让我们生产环境和开发环境很好的隔离配置,我们看看怎么做呢?

首先我们需要将之前的webpack.config.js分成三个文件 --- webpack.common.js,webpack.dev.js,webpack.prod.js.

webpack.common.js

这个是webpack的共同配置,总体和之前看到的大同小异,我们主要是导入了两个插件,一个是清除插件,一个是创建html的插件.

module.exports = {
entry: './src/index.js',plugins: [
new CleanWebpackPlugin(['dist']),new HtmlWebpackPlugin({title: 'webpack'}),new webpack.HashedModuleIdsPlugin()
],output: {
filename: '[name].[chunkhash].js',path: path.resolve(__dirname,'dist')
},module: {
rules: [
{
test: /.js?$/,query: {
presets: [
'react','es2015'
],plugins: ['react-html-attrs']
}
},{
test: /.css$/,use: ['style-loader','css-loader']
},{
test: /.(png|svg|jpg|gif)$/,use: ['file-loader']
},{
test: /.(woff|woff2|eot|ttf|otf)$/,{
test: /.(csv|tsv)$/,use: ['csv-loader']
},{
test: /.xml$/,use: ['xml-loader']
}
]
}
};

rules配置中我们也就是将一些可能用到的文件也配置到webpack中来,babel-loader这种如果要讲还可以再开一篇,其实就是个js的兼容性工具,这样理解就可以了.

webpack.dev.js

webpack开发环境的配置,非常简单,就是用了之前讲的webpack-merge工具,就和git一样,合并了webpack.common.js的配置外新加了可以进行调试的inline-source-map工具,以及热更新的内容索引.

module.exports = merge(common,{
devtool: 'inline-source-map',devServer: {
contentBase: './dist'
}
});

webpack.prod.js

webpack生产环境的配置,新加了一个压缩插件以及环境配置的插件,这里的开发工具和开发还款下的有所不同,具体可直接看官方文档.

module.exports = merge(common,{
devtool: 'source-map',plugins: [
new UglifyJSPlugin({sourceMap: true}),new webpack.DefinePlugin({
'process.env': {
'NODE_ENV': JSON.stringify('production')
}
})
]
});

terminal

这样我们就配置完成啦,我们在终端上输入看下效果:

首先我们进入到目录下并进行node包的安装.

npm run build

webpack@1.0.0 build /Users/zhushuangquan/Documents/code/webpack
webpack --config webpack.prod.js

clean-webpack-plugin: /Users/zhushuangquan/Documents/code/webpack/dist has been removed.
Hash: 85b65f54ef1436b295a5
Version: webpack 3.6.0
Time: 1148ms
Asset Size Chunks Chunk Names
main.014ac9aa420264da48eb.js 671 bytes 0 [emitted] main
main.014ac9aa420264da48eb.js.map 6.47 kB 0 [emitted] main
index.html 197 bytes [emitted]
[lVK7] ./src/index.js 184 bytes {0} [built]
Child html-webpack-plugin for "index.html":
1 asset
[3IRH] (webpack)/buildin/module.js 517 bytes {0} [built]
[DuR2] (webpack)/buildin/global.js 509 bytes {0} [built]

  • 2 hidden modules

我们可以看到已经打包好的文件:

main.014ac9aa420264da48eb.js

我们可以看到在webpack的打包和压缩下,代码已经基本不可读了. 所以我们需要加上之前的调试插件,以便生产环境出现bug后的补救.

npm start

webpack@1.0.0 start /Users/zhushuangquan/Documents/code/webpack
webpack-dev-server --open --config webpack.dev.js

clean-webpack-plugin: /Users/zhushuangquan/Documents/code/webpack/dist has been removed.
Project is running at http://localhost:8080/
webpack output is served from /
Content not from webpack is served from ./dist
webpack: wait until bundle finished: /
Hash: 06f20ec519d58fbd5c28
Version: webpack 3.6.0
Time: 1460ms
Asset Size Chunks Chunk Names
main.5eb4d4e3f458c49658a2.js 852 kB 0 [emitted] [big] main
index.html 197 bytes [emitted]
[6Um2] (webpack)/node_modules/url/util.js 314 bytes {0} [built]
[8o/D] (webpack)-dev-server/client/overlay.js 3.71 kB {0} [built]
[HPf+] (webpack)/node_modules/url/url.js 23.3 kB {0} [built]
[Lx3u] (webpack)/hot/log.js 1.04 kB {0} [optional] [built]
[Sj28] (webpack)-dev-server/node_modules/strip-ansi/index.js 161 bytes {0} [built]
[TfA6] (webpack)/hot nonrecursive ^.\/log$ 170 bytes {0} [built]
[U2me] (webpack)/hot/emitter.js 77 bytes {0} [built]
[V3KU] (webpack)-dev-server/client/socket.js 1.04 kB {0} [built]
[cMmS] (webpack)-dev-server/client?http://localhost:8080 7.27 kB {0} [built]
[gqsi] (webpack)-dev-server/node_modules/loglevel/lib/loglevel.js 7.74 kB {0} [built]
[0] multi (webpack)-dev-server/client?http://localhost:8080 ./src/index.js 40 bytes {0} [built]
[gt+Q] (webpack)-dev-server/node_modules/ansi-regex/index.js 135 bytes {0} [built]
[lVK7] ./src/index.js 184 bytes {0} [built]
[p7Vd] (webpack)/node_modules/punycode/punycode.js 14.7 kB {0} [built]
[pEPF] (webpack)/node_modules/querystring-es3/index.js 127 bytes {0} [built]

  • 73 hidden modules
    Child html-webpack-plugin for "index.html":
    1 asset
    [3IRH] (webpack)/buildin/module.js 517 bytes {0} [built]
    [DuR2] (webpack)/buildin/global.js 509 bytes {0} [built]
    [M4fF] ./node_modules/lodash/lodash.js 540 kB {0} [built]
    [a/t9] ./node_modules/html-webpack-plugin/lib/loader.js!./node_modules/html-webpack-plugin/default_index.ejs 538 bytes {0} [built]
    webpack: Compiled successfully.

我们可以看到打开了一个内容为Hello webpack的网页在8080端口,当我们修改文件时候网页会自动刷新.

知识点:

回到我们刚才的package.json的命令行配置来看.

  • 上面的npm run build => webpack => webpack.prod.js,就是执行了生产环境的配置的打包命令.
  • 上面的npm start => webpack-dev-server --open => webpack.dev.js,就是执行了开发环境配置的服务端命令.
  • --config是用于执行webpack配置文件的命令,而默认为webpack.config.js.
  • webpack命令就是和之前的gulp的逻辑相似,将entry实例复制到output路径的逻辑. 当然还伴随着一系列的操作.
  • webpack-dev-server --open命令是打开服务器并进行热加载的用途.

以上就是webpack的使用及逻辑,并没有想象中的复杂吧,甚至可以说是简单,实测一天即可入门webpack.

由于webpack的配置是固定代码,我已经打包上传github,需要的同学可以进行下载.

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持编程之家。

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