Basics - Lists & keys example 2.

App.js

import React, { Component } from "react";

export class App extends Component {
  render() {
    const todos = [
      { id: 1, text: "do something" },
      { id: 2, text: "do something else" },
      { id: 3, text: "do nothing" }
    ];
    const todoItems = todos.map(todo => <li key={todo.id}>{todo.text}</li>);

    return <div>{todoItems}</div>;
  }
}

export default App;