6 个提高 React 代码质量的方法 - 让你的 React 代码更简洁
前端宇宙
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·
2021-05-06 01:13
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。
不要用三元运算符,而是要用
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:改进后的代码: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>
)
}
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:改进后的代码: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>
)
}
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>
)
改进后的代码:
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。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>
)
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>
)
改进后的代码:
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onClick
或 onChange
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)} />
</>
)
}
改进后的代码:
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 />} />
)
改进后的代码:
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,我们尽量避免这个,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。以上6个优化后的React 代码片段,如果您认为对您有帮助,请记得 点赞、留言、分享和收藏 哦~~
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