问TypeError:从服务器获取数据时，无法读取未定义的属性“”map“”

EN

import React, { Component } from 'react';
import Toolbar from '../../components/Navigation/Toolbar/Toolbar';
import Order from '../../components/Order/Order';
import axios from 'axios';

class Orders extends Component {

    constructor(){
        super();
        this.state={
            orders:[]
        }

        this.componentDidMount=(event) =>{

            axios.get('https://reactjs-burger-builder-2607.firebaseio.com/orders.json')
              .then(response =>{
                console.log(response.data)
                let updatedOrders=[];
                for(let key in response.data)
                {
                    updatedOrders.push(response.data[key]);
                }
                this.setState({
                    orders:[].concat(updatedOrders),
                });
            })
        }     
}

  render() { 

      console.log(this.state.orders);

      let allOrders='loading..'; 
      if(this.state.orders){
          allOrders= <Order orders={this.state.orders}/>
      }

    return (
        <div>
        <Toolbar/>
        {allOrders}
        </div>    
    );
  }
}

export default Orders;

import React from 'react';
import classes from './Order.css';

const Order =(props) =>{

    console.log(props.orders);

    return(  
        <div>
         {props.orders.map(order =>
          <div className={classes.order} key={Math.random()}>
              <span>name: {order.name} </span><br/>
              <span>contact: {order.contact} </span><br/>
              <span>address: {order.address} </span><br/>
              <span>Price: {order.price} Rs </span><br/>
              <p><span>ingredients: </span>
              {order.ingredients.map(ingredient =>
                 <span key={Math.random()} className={classes.ingredients}>{ingredient.name} ({ingredient.qty}) </span>
               )}
              </p>
         </div>
        )}

        </div>
    );
}

export default Order;