javascript - 为什么在尝试显示组件中的每个对象值时出现“no-unused-expressions”错误

Question

我正在尝试使用 Todos 组件中的地图功能显示 Todo 标题。但是我收到错误消息：

第 6 行：期望一个赋值或函数调用，而是看到一个表达式 no-unused-expressions

Todos.js：

import React, { Component } from 'react';


class Todos extends Component {
  render() {
    return this.props.todos.map(todo => {
        <h3>{todo.title}</h3>
    });
    };
};

export default Todos;

应用程序.js：

import React, { Component } from 'react';
import Todos from './components/Todos';
import './App.css';

class App extends Component {
  state = {
    todos: [
      {
        id: 1,
        title: 'Take out the trash',
        completed: false
      },
      {
        id: 2,
        title: 'Dinner with wife',
        completed: false
      },
      {
        id: 3,
        title: 'Meeting with boss',
        completed: false
      },
    ]
  }

  render() {

    return (
      <div className="App">
        <Todos todos={this.state.todos} />   
      </div>
    );
  }
}

export default App;

索引.js：

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import * as serviceWorker from './serviceWorker';

ReactDOM.render(<App />, document.getElementById('root'));

serviceWorker.unregister();

标签： javascriptreactjs

Answer 1

缺少退货：

import React, { Component } from 'react';

class Todos extends Component {
  render() {
    return this.props.todos.map(todo => {
        return (
          <h3>{todo.title}</h3>
        );
    });
  }
}

export default Todos;