List.js

import React from 'react';

export default class List extends React.Component {
  render() {
    let names = this.props.names.map((person, index) => {
      return (
        <div id="person" key={person + index}>
          <div>Hello {person.firstName}</div>
          <div>{person.lastName}</div>
        </div>
      )
    });
    return (
      <div>
        {names}
      </div>
    )
  }
}

List.propTypes = {
  names: React.PropTypes.array
}