React

by Vlad Rasenko

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 = {
    	selectAll: false,
    	items: [
      	{ text: "Learn JavaScript", done: false },
        { text: "Learn React", done: false },
        { text: "Play around in JSFiddle", done: true },
        { text: "Build something awesome", done: true }
      ]
    }
    
    this.handleSelectAll = e => this.setState(({items, selectAll}) => ({
          	selectAll: !selectAll,
          	items: items.map(item => ({
            	...item,
            	done: !selectAll
            }))
          }))
          
    this.handleSelect = (item, index) => () => this.setState(({items}) => {
    	const nextItems = items.slice(0, index).concat({...item, done: !item.done}, items.slice(index + 1))
			const selectAll = nextItems.reduce((acc, item) => acc && item.done, true)
			return {
      	items: nextItems,
        selectAll
      }
    })
  }
  
  render() {
    return (
      <div>
        <h2>Todos:</h2>
        <ol>
        <li>
          <input type="checkbox" checked={this.state.selectAll} onChange={this.handleSelectAll} />
          <span>Select All</span>
        </li>
        <li>
          <hr/>
        </li>
        {this.state.items.map((item, i) => (
          <li key={i}>
            <label>
              <input type="checkbox" checked={item.done} onChange={this.handleSelect(item, i)} /> 
              <span className={item.done ? "done" : ""}>{item.text}</span>
            </label>
          </li>
        ))}
        </ol>
      </div>
    )
  }
}

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