问排序的reactjs常量状态

EN

class Messages extends Component {

  state = {
    messages: [],
    messagesDefault: []
  };

  componentDidMount() {
    this.props.getMessages();
  }

  componentWillReceiveProps(nextProps) {
    console.log(333)

    this.setState({
      messages: nextProps.messages.messages,
      messagesDefault: nextProps.messages.messages
    })
  }

  onSort(type) {
    // when i call this function both arrays are changing, but i need this.state.messagesDefault to stay by default
    let messagesDefault = this.state.messagesDefault;
    if (type === 'all') {

    } else if (type === 'new') {
      messagesDefault.sort((a, b) => (a.notReaded) ? -1 : (a.lastMessage === b.lastMessage) ? -1 : 1);
    } else if (type === 'deal') {
      messagesDefault.sort((a, b) => (a.lastMessage === b.lastMessage) ? 1 : (a.accpet && a.accpet.author && a.accpet.executor) ? -1 : 1);
    }
    // console.log(messagesDefault)
    this.setState({messages: messagesDefault})
  }

  render() {
    console.log(this.state.messages)
    return (
      <div>
</div>
)
}
}