https://facebook.github.io/react/docs/jsx-in-depth.html#javascript-expressions

You can pass any JavaScript expression as children, by enclosing it within {}. For example, these expressions are equivalent:

<MyComponent>foo</MyComponent>

<MyComponent>{'foo'}</MyComponent>

This is often useful for rendering a list of JSX expressions of arbitrary length. For example, this renders an HTML list:

function Item(props) {
  return <li>{props.message}</li>;
}

function TodoList() {
  const todos = ['finish doc', 'submit pr', 'nag dan to review'];
  return (
    <ul>
      {todos.map((message) => <Item key={message} message={message} />)}
    </ul>
  );
}

class First extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      data: [{name: 'bob'}, {name: 'chris'}],
    };
  }
  
  render() {
    return (
      <ul>
        {this.state.data.map(d => <li key={d.name}>{d.name}</li>)}
      </ul>
    );
  }
}

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

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
<div id="root"></div>