如何编写简洁的React代码

这篇文章给大家介绍如何编写简洁的React代码，内容非常详细，感兴趣的小伙伴们可以参考借鉴，希望对大家能有所帮助。

只对一个条件进行条件性渲染

如果你需要在一个条件为真时有条件地呈现一些东西，在一个条件为假时不呈现任何东西，不要使用三元运算符。使用&&运算符代替。

糟糕的例子:

import React, { useState } from 'react'  export const ConditionalRenderingWhenTrueBad = () => {   const [showConditionalText, setShowConditionalText] = useState(false)    const handleClick = () =>     setShowConditionalText(showConditionalText => !showConditionalText)    return (     
       Toggle the text       {showConditionalText ? 
The condition must be true!
 : null}     
   ) }

好的例子:

import React, { useState } from 'react'  export const ConditionalRenderingWhenTrueGood = () => {   const [showConditionalText, setShowConditionalText] = useState(false)    const handleClick = () =>     setShowConditionalText(showConditionalText => !showConditionalText)    return (     
       Toggle the text       {showConditionalText && 
The condition must be true!
}     
   ) }

有条件的渲染是指在任何条件下

如果你需要在一个条件为真时有条件地呈现一个东西，在条件为假时呈现另一个东西，请使用三元运算符。

糟糕的例子:

import React, { useState } from 'react'  export const ConditionalRenderingBad = () => {   const [showConditionOneText, setShowConditionOneText] = useState(false)    const handleClick = () =>     setShowConditionOneText(showConditionOneText => !showConditionOneText)    return (     
       Toggle the text       {showConditionOneText && 
The condition must be true!
}       {!showConditionOneText && 
The condition must be false!
}     
   ) }

好的例子:

import React, { useState } from 'react'  export const ConditionalRenderingGood = () => {   const [showConditionOneText, setShowConditionOneText] = useState(false)    const handleClick = () =>     setShowConditionOneText(showConditionOneText => !showConditionOneText)    return (     
       Toggle the text       {showConditionOneText ? (         
The condition must be true!
       ) : (         
The condition must be false!
       )}     
   ) }

Boolean props

一个真实的props可以提供给一个组件，只有props名称而没有值，比如：myTruthyProp。写成myTruthyProp={true}是不必要的。

糟糕的例子:

import React from 'react'  const HungryMessage = ({ isHungry }) => (   {isHungry ? 'I am hungry' : 'I am full'} )  export const BooleanPropBad = () => (   
            This person is hungry:                
            This person is full:              
 )

好的例子:

import React from 'react'  const HungryMessage = ({ isHungry }) => (   {isHungry ? 'I am hungry' : 'I am full'} )  export const BooleanPropGood = () => (   
            This person is hungry:                
            This person is full:              
 )

String props

可以用双引号提供一个字符串道具值，而不使用大括号或反斜线。

糟糕的例子:

import React from 'react'  const Greeting = ({ personName }) => 
Hi, {personName}!
  export const StringPropValuesBad = () => (   
                  
 )

好的例子:

import React from 'react'  const Greeting = ({ personName }) => 
Hi, {personName}!
  export const StringPropValuesGood = () => (   
                  
 )

事件处理函数

如果一个事件处理程序只需要事件对象的一个参数，你就可以像这样提供函数作为事件处理程序：onChange={handleChange}。

你不需要像这样把函数包在一个匿名函数中。

糟糕的例子:

import React, { useState } from 'react'  export const UnnecessaryAnonymousFunctionsBad = () => {   const [inputValue, setInputValue] = useState('')    const handleChange = e => {     setInputValue(e.target.value)   }    return (     <>       Name:         handleChange(e)} />        ) }

好的例子:

import React, { useState } from 'react'  export const UnnecessaryAnonymousFunctionsGood = () => {   const [inputValue, setInputValue] = useState('')    const handleChange = e => {     setInputValue(e.target.value)   }    return (     <>       Name:                ) }

将组件作为props传递

当把一个组件作为props传递给另一个组件时，如果该组件不接受任何props，你就不需要把这个传递的组件包裹在一个函数中。

糟糕的例子:

import React from 'react'  const CircleIcon = () => (    )  const ComponentThatAcceptsAnIcon = ({ IconComponent }) => (   
     
Below is the icon component prop I was given:
        
 )  export const UnnecessaryAnonymousFunctionComponentsBad = () => (    } /> )

好的例子:

import React from 'react'  const CircleIcon = () => (    )  const ComponentThatAcceptsAnIcon = ({ IconComponent }) => (   
     
Below is the icon component prop I was given:
        
 )  export const UnnecessaryAnonymousFunctionComponentsGood = () => (    )

为定义的props

未定义的props被排除在外，所以如果props未定义是可以的，就不要担心提供未定义的回退。

糟糕的例子:

import React from 'react'  const ButtonOne = ({ handleClick }) => (   Click me )  const ButtonTwo = ({ handleClick }) => {   const noop = () => {}    return Click me }  export const UndefinedPropsBad = () => (   
           alert('Clicked!')} />           alert('Clicked!')} />   
 )

好的例子:

import React from 'react'  const ButtonOne = ({ handleClick }) => (   Click me )  export const UndefinedPropsGood = () => (   
           alert('Clicked!')} />   
 )

设置依赖前一个状态的状态

如果新的状态依赖于之前的状态，那么一定要把状态设置为之前状态的函数。React的状态更新可以是分批进行的，如果不这样写你的更新就会导致意外的结果。

糟糕的例子:

import React, { useState } from 'react'  export const PreviousStateBad = () => {   const [isDisabled, setIsDisabled] = useState(false)    const toggleButton = () => setIsDisabled(!isDisabled)    const toggleButton2Times = () => {     for (let i = 0; i < 2; i++) {       toggleButton()     }   }    return (     
                I'm {isDisabled ? 'disabled' : 'enabled'}              Toggle button state       Toggle button state 2 times     
   ) }

好的例子:

import React, { useState } from 'react'  export const PreviousStateGood = () => {   const [isDisabled, setIsDisabled] = useState(false)    const toggleButton = () => setIsDisabled(isDisabled => !isDisabled)    const toggleButton2Times = () => {     for (let i = 0; i < 2; i++) {       toggleButton()     }   }    return (     
                I'm {isDisabled ? 'disabled' : 'enabled'}              Toggle button state       Toggle button state 2 times     
   ) }

总结

以下做法并非针对React，而是在JavaScript(以及任何编程语言)中编写干净代码的良好做法。

• 将复杂的逻辑提取为明确命名的函数

• 将神奇的数字提取为常量

• 使用明确命名的变量

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