githubUserList.js

const Card = (props) => {
	return (
  	<div style={{margin: '1em'}}>
    	<img width="75" src={props.avatar_url} />
      <div style={{display: 'inline-block', marginLeft: 10}}>
      	<div style={{fontSize: '1.25em', fontWeight: 'bold'}}>{props.name}</div>
        <div>{props.company}</div>
      </div>
  	</div>
  );
};

const CardList = (props) => {
	return (
  	<div>
    	{props.cards.map(card => <Card key={card.id} {...card} />)}
    </div>
  );
};

class Form extends React.Component {
	state = {username: ''}
  
	handleSubmit = (event) => {
  	event.preventDefault();
    axios.get(`https://api.github.com/users/${this.state.username}`).then(resp => {
    	this.props.submitCard(resp.data);
      this.setState({ username: '' });
    });
  };

	render() {
  	return(
    	<form onSubmit={this.handleSubmit}>
      	<input type="text" 
       	value={this.state.username}
        onChange={(event) => this.setState({ username: event.target.value})}
        placeholder="Github username" required />
        <button type="submit">Add card</button>
      </form>
    )
  }
}

class App extends React.Component {
	state = {
  	cards: []
	};
  
  addNewCard = (cardInfo) => {
  	this.setState(prevState => ({
    	cards: prevState.cards.concat(cardInfo)
    }));
  };
  
	render() {
    return (
  	<div>
    	<Form submitCard={this.addNewCard} />
      <CardList cards={this.state.cards} />
    </div>
  );
  }
}

ReactDOM.render(<App />, mountNode);