初步学习next.js-5-编写css样式和lazyloading

CSS

import React, {useState} from 'react'

function Jspang(){
    //关键代码----------start-------
    const [color,setColor] = useState('blue')

    const changeColor=()=>{

        setColor(color=='blue'?'red':'blue')
    }
     //关键代码----------end-------

    return (
        <>
            <div>技术胖免费前端教程</div>
            <div><button onClick={changeColor}>改变颜色</button></div>
            <style jsx>
                {`
                    div { color:${color};}
                `}
            </style>
        </>
    )
}
export default Jspang

懒加载

　　懒加载模块

　

import React, {useState} from 'react'
//删除import moment
function Time(){

    const [nowTime,setTime] = useState(Date.now())

    const changeTime= async ()=>{ //把方法变成异步模式
        const moment = await import('moment') //等待moment加载完成
        setTime(moment.default(Date.now()).format()) //注意使用defalut
    }
    return (
        <>
            <div>显示时间为:{nowTime}</div>
            <div><button onClick={changeTime}>改变时间格式</button></div>
        </>
    )
}
export default Time

　　懒加载组件

export default ()=><div>Lazy Loading Component</div>

import React, {useState} from 'react'
import dynamic from 'next/dynamic'

const One = dynamic(import('../components/one'))

function Time(){

    const [nowTime,setTime] = useState(Date.now())

    const changeTime= async ()=>{
        const moment = await import('moment')

        setTime(moment.default(Date.now()).format())
    }
    return (
        <>
            <div>显示时间为:{nowTime}</div>
            <One/>
            <div><button onClick={changeTime}>改变时间格式</button></div>
        </>
    )
}
export default Time