Javascript 当试图在React中呈现组件时,应获得赋值或函数调用,而不是看到一个表达式没有未使用的表达式错误
我试图根据items对象中的项数渲染卡组件,但在第6行出现错误Javascript 当试图在React中呈现组件时,应获得赋值或函数调用,而不是看到一个表达式没有未使用的表达式错误,javascript,reactjs,Javascript,Reactjs,我试图根据items对象中的项数渲染卡组件,但在第6行出现错误 import React from "react"; export class Cards extends React.Component { render() { let elements = []; elements = this.props.items.map(item => { <Card titles = {item.title} imgs
import React from "react";
export class Cards extends React.Component {
render() {
let elements = [];
elements = this.props.items.map(item => {
<Card titles = {item.title} imgsrc = {item.urlToImage}
discr = {item.description} urls = {item.url}
/>
})
return (
{elements}
);
}
}
您没有在.map中返回JSX,您需要这样做:
import React from "react";
export class Cards extends React.Component {
render() {
let elements = [];
elements = this.props.items.map(item => {
return <Card titles = {item.title} imgsrc = {item.urlToImage}
discr = {item.description} urls = {item.url}
/>
})
return (
{elements}
);
}
}
或者以更干净的方式:
import React from "react";
export class Cards extends React.Component {
render() {
return (
{this.props.items.map(item => {
return <Card titles = {item.title} imgsrc = {item.urlToImage}
discr = {item.description} urls = {item.url}
/>
})}
);
}
}
您没有在.map中返回JSX,您需要这样做:
import React from "react";
export class Cards extends React.Component {
render() {
let elements = [];
elements = this.props.items.map(item => {
return <Card titles = {item.title} imgsrc = {item.urlToImage}
discr = {item.description} urls = {item.url}
/>
})
return (
{elements}
);
}
}
或者以更干净的方式:
import React from "react";
export class Cards extends React.Component {
render() {
return (
{this.props.items.map(item => {
return <Card titles = {item.title} imgsrc = {item.urlToImage}
discr = {item.description} urls = {item.url}
/>
})}
);
}
}
作为第一个答案,您需要在map中返回JSX 或者在映射中使用而不是{} 像这样
import React from "react";
export class Cards extends React.Component {
render() {
return (
{this.props.items.map(item => (
return <Card titles = {item.title} imgsrc = {item.urlToImage}
discr = {item.description} urls = {item.url}
/>
))}
);
}
}
作为第一个答案,您需要在map中返回JSX 或者在映射中使用而不是{} 像这样
import React from "react";
export class Cards extends React.Component {
render() {
return (
{this.props.items.map(item => (
return <Card titles = {item.title} imgsrc = {item.urlToImage}
discr = {item.description} urls = {item.url}
/>
))}
);
}
}
你的.map回调没有返回任何内容。请尝试返回JSX。您的.map回调没有返回任何内容。尝试返回JSX。