6 个提高 React 代码质量的方法 - 让你的 React 代码更简洁

简洁的代码具有更好的可读性,容易理解,且易于组织。

本篇文章介绍 6 个在 React 中写简洁代码的技巧。

1. 条件渲染(一个条件时)

当你要根据条件来判断,以渲染不同的组件时,比如条件满足(为 true) 时,就渲染组件,否则不渲染(渲染空内容),这种情况下
不要用三元运算符,而是要用 && 这个操作符来处理,看下面的例子:

不好的代码

import React, { useState } from 'react'

export const ConditionalRenderingWhenTrueBad = () => {
  const [showConditionalText, setShowConditionalText] = useState(false)

  const handleClick = () =>
    setShowConditionalText(showConditionalText => !showConditionalText)

  return (
    <div>
      <button onClick={handleClick}>Toggle the text</button>
      {showConditionalText ? <p>The condition must be true!</p> : null}
    </div>
  )
}

好的代码

import React, { useState } from 'react'

export const ConditionalRenderingWhenTrueGood = () => {
  const [showConditionalText, setShowConditionalText] = useState(false)

  const handleClick = () =>
    setShowConditionalText(showConditionalText => !showConditionalText)

  return (
    <div>
      <button onClick={handleClick}>Toggle the text</button>
      {showConditionalText && <p>The condition must be true!</p>}
    </div>
  )
}

2. 条件渲染(不同的条件时)

跟上面的情况有点像,也是根据条件来判断渲染的组件,只是条件不满足时不再渲染空内容,而是渲染别的组件内容。

这个时候应该用三元运算符。

不好的代码

import React, { useState } from 'react'

export const ConditionalRenderingBad = () => {
  const [showConditionOneText, setShowConditionOneText] = useState(false)

  const handleClick = () =>
    setShowConditionOneText(showConditionOneText => !showConditionOneText)

  return (
    <div>
      <button onClick={handleClick}>Toggle the text</button>
      {showConditionOneText && <p>The condition must be true!</p>}
      {!showConditionOneText && <p>The condition must be false!</p>}
    </div>
  )
}

好的代码

import React, { useState } from 'react'

export const ConditionalRenderingGood = () => {
  const [showConditionOneText, setShowConditionOneText] = useState(false)

  const handleClick = () =>
    setShowConditionOneText(showConditionOneText => !showConditionOneText)

  return (
    <div>
      <button onClick={handleClick}>Toggle the text</button>
      {showConditionOneText ? (
        <p>The condition must be true!</p>
      ) : (
        <p>The condition must be false!</p>
      )}
    </div>
  )
}

3. 布尔值属性

我们经常会传一个布尔类型的属性 (props) 给组件,类似 myTruthyProp={true} 这样的写法是没有必要的。

不好的代码

import React from 'react'

const HungryMessage = ({ isHungry }) => (
  <span>{isHungry ? 'I am hungry' : 'I am full'}</span>
)

export const BooleanPropBad = () => (
  <div>
    <span>
      <b>This person is hungry: </b>
    </span>
    <HungryMessage isHungry={true} />
    <br />
    <span>
      <b>This person is full: </b>
    </span>
    <HungryMessage isHungry={false} />
  </div>
)

好的代码

import React from 'react'

const HungryMessage = ({ isHungry }) => (
  <span>{isHungry ? 'I am hungry' : 'I am full'}</span>
)

export const BooleanPropGood = () => (
  <div>
    <span>
      <b>This person is hungry: </b>
    </span>
    <HungryMessage isHungry />
    <br />
    <span>
      <b>This person is full: </b>
    </span>
    <HungryMessage isHungry={false} />
  </div>
)

这样更简洁点,虽然只是一个小小技巧,但是可以从中看出你是不是一个有经验且优秀的程序员。

4. 字符串属性

跟上面的例子差不多,只是换成了字符串类型,这个时候,我们通常用双引号把字符串括起来,再加上花括号,如下面这样:

不好的代码

import React from 'react'

const Greeting = ({ personName }) => <p>Hi, {personName}!</p>

export const StringPropValuesBad = () => (
  <div>
    <Greeting personName={"John"} />
    <Greeting personName={'Matt'} />
    <Greeting personName={`Paul`} />
  </div>
)

好的代码

import React from 'react'

const Greeting = ({ personName }) => <p>Hi, {personName}!</p>

export const StringPropValuesGood = () => (
  <div>
    <Greeting personName="John" />
    <Greeting personName="Matt" />
    <Greeting personName="Paul" />
  </div>
)

5. 事件绑定函数

我们经常会给一个组件绑定类似 onClickonChange 这样的事件,比如我们可能会这样写:onChange={e => handleChange(e)},其实是没必要的,且看:

不好的代码

import React, { useState } from 'react'

export const UnnecessaryAnonymousFunctionsBad = () => {
  const [inputValue, setInputValue] = useState('')

  const handleChange = e => {
    setInputValue(e.target.value)
  }

  return (
    <>
      <label htmlFor="name">Name: </label>
      <input id="name" value={inputValue} onChange={e => handleChange(e)} />
    </>
  )
}

好的代码

import React, { useState } from 'react'

export const UnnecessaryAnonymousFunctionsGood = () => {
  const [inputValue, setInputValue] = useState('')

  const handleChange = e => {
    setInputValue(e.target.value)
  }

  return (
    <>
      <label htmlFor="name">Name: </label>
      <input id="name" value={inputValue} onChange={handleChange} />
    </>
  )
}

6. 组件属性

跟上面的例子差不多,我们也可以把组件作为属性传给别的组件,这个时候,支持使用把组件包成函数来传递,但没有接任何参数的时候,这种是没有必要的,且看:

不好的代码

import React from 'react'

const CircleIcon = () => (
  <svg height="100" width="100">
    <circle cx="50" cy="50" r="40" stroke="black" stroke-width="3" fill="red" />
  </svg>
)

const ComponentThatAcceptsAnIcon = ({ IconComponent }) => (
  <div>
    <p>Below is the icon component prop I was given:</p>
    <IconComponent />
  </div>
)

export const UnnecessaryAnonymousFunctionComponentsBad = () => (
  <ComponentThatAcceptsAnIcon IconComponent={() => <CircleIcon />} />
)

好的代码

import React from 'react'

const CircleIcon = () => (
  <svg height="100" width="100">
    <circle cx="50" cy="50" r="40" stroke="black" stroke-width="3" fill="red" />
  </svg>
)

const ComponentThatAcceptsAnIcon = ({ IconComponent }) => (
  <div>
    <p>Below is the icon component prop I was given:</p>
    <IconComponent />
  </div>
)

export const UnnecessaryAnonymousFunctionComponentsGood = () => (
  <ComponentThatAcceptsAnIcon IconComponent={CircleIcon} />
)

总结

有时候写代码我们并没有注意到,多写一行,或多写内容有什么问题,但是有时候是没有必要的,我们尽量僻免这个,写出更好,更简洁的代码,这样别人能认为你是个有经验的程序员。