reactintro_render_refactored.jsx

...

import TextField from './TextField';

class SimpleForm extends React.Component {
  ...

  render() {
    const { firstNameError, firstName, lastName, lastNameError } = this.state;

    return (
      <div style={style.form}>
        <TextField name="firstName"
                   label="First name:"
                   onChange={this.onFirstNameChange}
                   onBlur={this.onFirstNameBlur}
                   error={firstNameError} />

        <TextField name="lastName"
                   label="Last name:"
                   onChange={this.onLastNameChange}
                   onBlur={this.onLastNameBlur}
                   error={lastNameError} />

        <Greetings firstName={firstName} lastName={lastName} />
      </div>
    );
  }
}