javascript - react js-×类型错误: Cannot read property 'map' of undefined

Question

我对这段代码有疑问: 类型错误:无法读取未定义的属性“map”

请指导我该怎么做

app.js

import React from "react";

import {CardList} from "./componets/card-list/card-list";


class App extends React.Component {
    constructor() {
        super();
        this.state={
            monsters:
                []
        };
    }
    componentDidMount() {
        fetch('http://jsonplaceholder.typicode.com/users')
            .then(res => res.json())
            .then((data) => {
                this.setState({ monsters: data })
            })
    }
    render() {
     return(
         <div>
             <CardList monters={this.state.monsters}/>
         </div>
     )
 }
}
export default App;

和cardlist.jsx请指导我该怎么做

import './card-list.css'


export const CardList=(props) => (

     <div className='card-list'>{props.monsters.map(monster =>(<h1 key={monster.id}>{monster.name}</h1>))}

    </div>
);```

Answer 1

你错过了这里:

<CardList monters={this.state.monsters}/>

你将你的 Prop 命名为monters