React

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

function getItems() {
	return Array.from({ length: 6 }).map((_, i) => <p>{i}</p>);
}

function discardWarning(args) {
	return React.createElement(React.Fragment, null, ...args);
}


class App extends React.Component {
  render() {
    return (
      <div>
        <div>
          {getItems()}
        </div>
        <div>
          {discardWarning(getItems())}
        </div>
      </div>
    )
  }
}

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