How to split page code and load on demand-JS Tutorial-php.cn

This time I will show you how to split the page code and load it on demand. What are theprecautions. Here is a practical case, let's take a look.

Modify configuration

Development environment: webpack@v3, react-router@v4

InstallationDependencies:

$ yarn add babel-plugin-syntax-dynamic-import -dev

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Modify the .babelrc file: add "syntax-dynamic-import" in plugins

Modify the project code

Install dependencies:

$ yarn add react-loadable

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According to the react-loadable documentation, we need to provide a Loading component when loading a new page, and also provide different prompts for loading and timeout status:

import React from 'react'; import { Icon } from 'antd'; const Loading = ({ pastDelay, timedOut, error }) => { if (pastDelay) { return 
; } else if (timedOut) { return Taking a long time...
; } else if (error) { return Error!
; } return null; };

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Change the page component import method:

import React from 'react'; import Loadable from 'react-loadable'; import { Route, Switch } from 'react-router-dom'; const Home = Loadable({ loader: () => import('../Home'), loading: Loading, timeout: 10000 }); const EditArticle = Loadable({ loader: () => import('../EditArticle'), loading: Loading, timeout: 10000 }); ...

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Then the packaging results will separate the codes of each page:

In the page we only need to load theentry fileapp.js, other scripts are in This file will be loaded when the corresponding page is accessed.

Verification results

After uploadingstaticresources to cdn, load app.css and app.js in the page, and access after running Each page will load the corresponding script in turn. The result is as shown in the figure:

#It can be seen that the page script loaded when accessing the first page is only 21.8 after gzip compression. KB! ! ! Of course, this is also related to the complexity of the page, but compared with loading all scripts, it has been greatly reduced. This optimization is particularly obvious to users with highly targeted access.

Another benefit of doing this is that when we only change the business code of some pages in the project, the code of other pages remains unchanged, so at this time other pages use client cache. Another level of optimization has been done.

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!