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This lesson explains the
webpack v4SCSS extraction and lazy loading in. It is worth mentioning that there is av4v3huge difference between the methods of handling lazy loading on Scss.
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1. Preparatory workFor the basics of SCSS processing, refer to the Webpack4 Series tutorial (vi): Handling SCSS.
This lesson mainly deals with the related configuration and plug-in used by SCSS under lazy loading.
This shows the structure of the Directory code:
In order to achieve SCSS lazy loading, we used a extract-text-webpack-plugin plugin.
Note that you should install the v4 version extract-text-webpack-plugin for the plugin when installing it . NPM runs the following command:npm install --save-dev extract-text-webpack-plugin@next
The rest of the configuration is similar to lesson six. The package.json configuration is as follows:
{ "devDependencies": { "css-loader": "^1.0.0", "extract-text-webpack-plugin": "^4.0.0-beta.0", "node-sass": "^4.9.2", "sass-loader": "^7.0.3", "style-loader": "^0.21.0", "webpack": "^4.16.0" }}
About the style file under our Scss file base.scss :
// 网站默认背景色：red$bgColor: red !default;*,body { margin: 0; padding: 0;}html { background-color: $bgColor;}
common.scss:
2. Use// 覆盖原来颜色：greenhtml { background-color: green !important;}
ExtractTextPluginTo use extract-text-webpack-plugin , you need to webpack.config.js configure the options in plugins and rules scss the related options in.
webpack.config.js:
const PATH = require ("path"), const Extracttextplugin = require (" Extract-text-webpack-plugin "); module.exports = {entry: {app:"./src/app.js "}, Output: {publicpath: __dirname + "/dist/", Path:path.resolve (__dirname, "dist"), FileName: "[name].bundle.js", Chunkfilename: "[name].chunk.js" }, module: {rules: [{test:/\.scss$/, Use:ExtractTextPlugin.extract ({//NOTE 1 Fallback: {loader: "Style-loader"}, use: [{loader: "Css-loader ", Options: {minimize:true}}, {loader:" s Ass-loader "}]})}]}, plugins: [New Extracttextplugin ({filename:" [Name ].min.css ", Allchunks:false//NOTE 2})]};
In the configuration, note the configuration items in 1 for the callback LOADER that css scss should be used for styles that are not extracted as separate files. style-loaderembed the Web page code with SCSS, even if it is processed into CSS.
Note that the 2 allChunks must be specified as false . Otherwise, it will include the asynchronous loaded css!
SCSSIn the project portal file app.js , for scss lazy loading, you need to introduce the following configuration code:
import "style-loader/lib/addStyles";import "css-loader/lib/css-base";
The rest of us first set the background color to red, after the user clicks the mouse, lazy loading common.scss , the background color turns green. The remaining code is as follows:
4. Packaging and introductionimport "./scss/base.scss";var loaded = false;window.addEventListener("click", function() { if (!loaded) { import(/* webpackChunkName: 'style'*/ "./scss/common.scss").then(_ => { // chunk-name : style console.log("Change bg-color of html"); loaded = true; }); }});
According to our app.js configuration in webpackChunkName , we can guess that there are: files in the package results style.chunk.js .
After the command line is webpack packaged, /dist/ the packaging results in the catalog are as follows:
Finally, we need to introduce the non-lazy-loaded style ( /dist/app.min.css ) and JS file () in the HTML code to the package results /dist/app.bundle.js .
<!DOCTYPE html>
End
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