react 首屏性能优化

Posted 2021-02-06 changyaoself

首屏优化点：1.加载包（bundle.js）文件的大小，越小，首屏渲染速度越快 (按需加载)

　　　　　　2.优先渲染用户直观看到的页面部分（懒加载）

 

技术点：react-loadable 、 react-lazyload

 

import React,{Component} from "react"
import {Link} from "react-router-dom"
import LazyLoad from ‘react-lazyload‘; //懒加载依赖
import Diag from "../component/diag"     //懒加载占位组件
import Loadable from ‘react-loadable‘; //按需加载依赖
import "../static/css/page2.scss"

const Loading = () => <div>Loading...</div>;

const Imgshow = Loadable({  //按需加载模块配置
    loader: () => import("../component/imgshow"),
    loading:Loading,
});

class B extends Component{
    state={
        pics:[
            require("../static/imgs/link.jpg"),
            require("../static/imgs/link1.jpg"),
            require("../static/imgs/link2.jpg"),
            require("../static/imgs/link3.jpg"),
            require("../static/imgs/link4.jpg"),
            require("../static/imgs/link5.jpg"),
            require("../static/imgs/link6.jpg"),
            require("../static/imgs/link7.jpg"),
            require("../static/imgs/link8.jpg"),
        ]
    };
    render(){
        return (
            <div>
                <ul className="lazyLi">
                    <li style={{height:"600px"}}></li>
                    {this.state.pics.map((item,index)=><li  key={index}>
                        <LazyLoad  height={200} placeholder={<Diag/>} debounce={200}>   //懒加载图片，当页面滚动此位置时，加载Imgshow组件
                            <Imgshow src={item}/>
                        </LazyLoad>
                    </li>)}
                </ul>
            </div>
        )
    }
}
export default B;

滚动前：

滚动后：

 多了一个4.chunk.js,页面滚动到此组件位置，采取加载此组件，减小了bundle 的文件大小，配合懒加载使用

 

react-lazyload : https://www.npmjs.com/package/react-lazyload