React

by Vasilii Chugunov

HTML

<div id="app"></div>

CSS

body {
  background: #20262E;
  padding: 20px;
  font-family: Helvetica;
}

#app {
  background: #fff;
  border-radius: 4px;
  padding: 20px;
  transition: all 0.2s;
}

li {
  margin: 8px 0;
}

h2 {
  font-weight: bold;
  margin-bottom: 15px;
}

.done {
  color: rgba(0, 0, 0, 0.3);
  text-decoration: line-through;
}

input {
  margin-right: 5px;
}

React

class TodoApp extends React.Component {
  constructor(props) {
    super(props)
    this.state = {
    	items: [
      	{ id: 'text1', text: "Learn JavaScript", done: false },
        { id: 'text2', text: "Learn React", done: false },
        { id: 'text3', text: "Play around in JSFiddle", done: true },
        { id: 'text4', text: "Build something awesome", done: true }
      ]
    }
  }
  
  toggleItem = id => {
    const { items } = this.state;
    const newItems = items.slice();
    const foundIndex = newItems.findIndex(item => item.id === id);
    
    newItems[foundIndex].done = !newItems[foundIndex].done;
    this.setState({ items: newItems });
  };
  
  render() {
    return (
      <div>
        <h2>Todos:</h2>
        <ol>
        {this.state.items.map(item => (
          <li key={item.id}>
            <label>
              <input type="checkbox" checked={item.done} onClick={() => this.toggleItem(item.id)} /> 
              <span className={item.done ? "done" : ""}>{item.text}</span>
            </label>
          </li>
        ))}
        </ol>
      </div>
    )
  }
}

ReactDOM.render(<TodoApp />, document.querySelector("#app"))