React가 목록을 렌더링하기 위해 특수 구성 요소를 사용하는 이유는 무엇입니까?

class MyComponent extends Component {
    render() {
        const {todos, user} = this.props;
        return (<div>
            {user.name}
            <ul>
                {todos.map(todo => <TodoView todo={todo} key={todo.id} />)}
            </ul>
        </div>)
    }
}

class MyComponent extends Component {
    render() {
        const {todos, user} = this.props;
        return (<div>
            {user.name}
            <TodosView todos={todos} />
        </div>)
    }
}

class TodosView extends Component {
    render() {
        const {todos} = this.props;
        return <ul>
            {todos.map(todo => <TodoView todo={todo} key={todo.id} />)}
        </ul>)
    }
}

import React, { Component } from 'react'
export default class App extends Component {
// 假设服务器端返回如下
state={books:['巴黎圣母院','悲惨世界','爱的教育','简·爱','钢铁是怎样炼成的','安徒生童话']}
booklist(){
// 把服务器端返回的字符串数组转换为JSX数组
let arr=[]
for(let i=0;i<this.state.books.length;i++){
arr.push( <li key={i}>《{this.state.books[i]}》</li> )
}
return arr
}
render() {
return (
<div>
<ul>
{this.booklist()}
</ul>
</div>
)
}
}

showList(){
return   this.state.list.map( (e,i)=>JSX )
}
{this.showList() }

import React, { Component } from 'react'
export default class App extends Component {
// 假设服务器端返回如下
state={books:['巴黎圣母院','悲惨世界','爱的教育','简·爱','钢铁是怎样炼成的','安徒生童话']}
booklist(){
// 把服务器端返回的字符串数组转换为JSX数组
return this.state.books.map( (b,i)=> <li key={i}>《{b}》</li> )
}
render() {
return (
<div>
<ul>
{this.booklist()}
</ul>
</div>
)
}
}

{
this.state.list.map( (e,i)=>JSX )
}

import React, { Component } from 'react'
export default class App extends Component {
// 假设服务器端返回如下
state={books:['巴黎圣母院','悲惨世界','爱的教育','简·爱','钢铁是怎样炼成的','安徒生童话']}
render() {
return (
<div>
<ul>
{/*this.booklist()*/}
{
/*此处不能急 编写for循环——for不是表达式*/
this.state.books.map( (b,i)=> <li key={i}>《{b}》</li> )
}
</ul>
</div>
)
}
}