【译】React代码整洁之道
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整洁的代码不仅仅是正常运行的代码，更是要求易于阅读、简单易懂、组织整齐。
在本文中，我们将研究八种代码整洁之道。
在阅读这些建议时，要记住这些只是建议！如果你不同意它们中的任何一个，那也完全没关系。
以下这些实践，个人觉得对我自己编写 React 代码很有帮助。
让我们开始吧！
1. 仅对一个条件进行渲染
如果需要在条件为 true 时渲染某些内容，而在条件为 false 时不渲染任何内容，不要使 三元表达式，请改用 &&。
🙅♂️ 不推荐示例：
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>
{/* 三元表达式 */}
{showConditionalText ? <p>条件为 True!</p> : null}
</div>
)
}
👍 推荐示例：
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>条件为 True!</p>}
</div>
)
}
2. 每一个条件都进行渲染
如果需要在条件为 true 时渲染某些内容，而在条件为 false 时渲染其他内容。使用三元表达式！
🙅♂️ 不推荐的示例：
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>
{/* 条件 True 和 False 都要渲染内容 */}
{showConditionOneText && <p>条件为 True!</p>}
{!showConditionOneText && <p>条件为 Flase!</p>}
</div>
)
}
👍 推荐示例：
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. Boolean props
Props 值为 true 的推荐省略不写。
🙅♂️ 不推荐示例：
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>
)
👍 推荐示例：
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>
{/* 不需要赋值 true，省略 */}
<HungryMessage isHungry />
<br />
<span>
<b>This person is full: </b>
</span>
<HungryMessage isHungry={false} />
</div>
)
4. String props
Props 值为 String, 使用双引号，不使用花括号或反引号。
🙅♂️ 不推荐示例：
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>
)
👍 推荐示例：
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. Event handler functions
如果一个事件函数只接受一个参数，不需要传入匿名函数：onChange={e=>handleChange（e）}，推荐这种写法：onChange={handleChange} 。
🙅♂️ 不推荐示例：
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>
{/* 事件只有一个参数，不需要匿名函数*/}
<input id="name" value={inputValue} onChange={e => handleChange(e)} />
</>
)
}
👍 推荐示例：
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. components as props
将组件作为参数传递给另一个组件时，如果该组件不接受任何参数，则无需将该传递的组件包装在函数中。
🙅♂️ 不推荐示例：
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 = () => (
{/* 组件不需要包装在函数中 */}
<ComponentThatAcceptsAnIcon IconComponent={() => <CircleIcon />} />
)
👍 推荐示例：
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} />
)
7. undefined props
如果参数为 undefined 是允许的，那么不要提供 undefined 作为回退值。
🙅♂️ 不推荐示例：
import React from 'react'
const ButtonOne = ({ handleClick }) => (
<button onClick={handleClick || undefined}>Click me</button>
)
const ButtonTwo = ({ handleClick }) => {
const noop = () => {}
return <button onClick={handleClick || noop}>Click me</button>
}
export const UndefinedPropsBad = () => (
<div>
<ButtonOne />
<ButtonOne handleClick={() => alert('Clicked!')} />
<ButtonTwo />
<ButtonTwo handleClick={() => alert('Clicked!')} />
</div>
)
👍 推荐示例：
import React from 'react'
const ButtonOne = ({ handleClick }) => (
<button onClick={handleClick}>Click me</button>
)
export const UndefinedPropsGood = () => (
<div>
<ButtonOne />
<ButtonOne handleClick={() => alert('Clicked!')} />
</div>
)
8. 设置 state 依赖先前的 state
如果新 state 依赖于先前 state，则始终将 state 设置为先前 state 的函数。可以批处理 React 状态更新。
🙅♂️ 不推荐示例：
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 (
<div>
<button disabled={isDisabled}>
I'm {isDisabled ? 'disabled' : 'enabled'}
</button>
<button onClick={toggleButton}>Toggle button state</button>
<button onClick={toggleButton2Times}>Toggle button state 2 times</button>
</div>
)
}
👍 推荐示例：
import React, { useState } from 'react'
export const PreviousStateGood = () => {
const [isDisabled, setIsDisabled] = useState(false)
{/* 推荐设置为函数 */}
const toggleButton = () => setIsDisabled(isDisabled => !isDisabled)
const toggleButton2Times = () => {
for (let i = 0; i < 2; i++) {
toggleButton()
}
}
return (
<div>
<button disabled={isDisabled}>
I'm {isDisabled ? 'disabled' : 'enabled'}
</button>
<button onClick={toggleButton}>Toggle button state</button>
<button onClick={toggleButton2Times}>Toggle button state 2 times</button>
</div>
)
}以上就是我推荐的几个写出整洁的 React 代码的实践。
最后，恭喜你读完了本文，欢迎留言交流~
原文地址：https://dev.to/thawkin3/react-clean-code-simple-ways-to-write-better-and-cleaner-code-2loa
翻译/润色：ViktorHub
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