JSX Compiler

JSX表現はJS変換時 React.createElement となる

// JSX
var HelloMessage = React.createClass({
  render: function() {
    return <div>Hello {this.props.name}</div>;
  }
});

React.render(<HelloMessage name="John" />, mountNode);

// native JS
var HelloMessage = React.createClass({displayName: "HelloMessage",
  render: function() {
    return React.createElement("div", null, "Hello ", this.props.name);
  }
});

React.render(React.createElement(HelloMessage, {name: "John"}), mountNode);

The JSX expression always evaluates to a ReactElement. The actual implementation details may vary. An optimized mode could inline the ReactElement as an object literal to bypass the validation code in React.createElement.