后端未收到请求

Question

我的项目将Angular用作前端和Node.js作为socket.io Integration的后端。

我正在尝试从Frontend发送帖子请求，如下所示：

Frontend

HTML中的按钮调用onorder（）方法：

 <button (click)="onOrder()" class="button">Checkout</button></div>

中的方法调用。

onOrder(){
    console.log('pressed'); // successfully logged to console
    if(this.itemsInCart.length > 0 ) {
      let order: SubmitOrderModel = new SubmitOrderModel();
      order.order = this.itemsInCart;
      this.webSocketService.fetchOrders(order);
    }
  }

​

export class AddToCartModel {
    thumbnail?: string = '';
    mealName: string = '';
    addons: string[] = [];
    variant?: string = '';
    cost: number = 0;
    quantity: number = 1;
}

export class SubmitOrderModel {
    order: AddToCartModel[] = [];
}

​

setupSocketConnection(){
        this.socket.on('fetchOrders', (data: string) => {
            console.log(data);
            localStorage.setItem('allOrders', JSON.stringify(data[0]));
          });
        this.socket.on('fetchRequests', (data: string) => {
            console.log(data);
            localStorage.setItem('allRequests', JSON.stringify(data[0]));
            StaffScreenComponent.allRequests = data;
          });

    
    }

    fetchOrders(order: SubmitOrderModel) {
        this.socket.emit('fetchOrders', order);
    } 

    OnFetchOrders() {
        return this.socket.fromEvent('fetchOrders');
    }

​

​：

var mongoose = require('mongoose');

var menuOrderSchema = mongoose.Schema;

var AddMenuOrderSchema = new menuOrderSchema({
    order: [{
        thumbnail: String,
        mealName: String,
        addons: [String],
        variant: {type: String, default: 'Standard'},
        cost: Number,
        quantity: Number
    }],
});

var newMenuOrderSchema = mongoose.model('addMenuOrderSchema', AddMenuOrderSchema );

module.exports = newMenuOrderSchema;

并且后端中的套接字配置如下：

io.on('connection', (socket)=>{
    console.log('connection')
      socket.on("fetchOrders", (arg) => {
        console.log('fetchOrders');
        const postMenuOrderM = new addMenuOrderModel(arg);
        console.log('checking')
        postMenuOrderM.save().then(function(){
          addMenuOrderModel.find().then(data=>{
                io.emit('fetchOrders', data)
            }).catch(err=>res.send(err));
          });
      });

    socket.on('disconnect', () => console.log('disconnected')); 
})

Node.js服务器未从UI接收任何呼叫。

我在这里做错了什么？