如何将一个类中定义的方法访问到 TypeScript 中的另一个类答案

【问题标题】：How to access the method defined in one class to another class in TypeScript如何将一个类中定义的方法访问到 TypeScript 中的另一个类
【发布时间】：2022-11-06 04:07:47
【问题描述】：

我已经导出了其中定义了handle() 方法的类，我只想在另一个类中访问这个方法。下面是我的代码：

客户.push.handler.ts

import { Inject } from "@nestjs/common";
import { EventsHandler, IEventHandler } from "@nestjs/cqrs";
import { CustomerPushEvent } from "../events/customer.push.events";
const admin = require('firebase-admin');

@EventsHandler(CustomerPushEvent)
export class CustomerPushEventHandler implements IEventHandler<CustomerPushEvent>{
  constructor(
     @Inject('Logger') private readonly log,
  ) {}

async handle(customerEvent:CustomerPushEvent){

    try{

        const message = {
            topic: String(customerEvent.customerId),
            notification: {
                title:'Dummy notification',
                body: 'New Shipment !!',
            },
            android: {
                collapse_key: 'messages',
                priority: 'HIGH',
            },
        };
      
        // Send a message to the device corresponding to the provided
        // registration token.
        admin
            .messaging()
            .send(message)
            .then(response => {
                console.log('Truck has been assigned:', message);
                console.log('Customer event',customerEvent);
            })
            .catch(error => {
                console.log('Error sending message:', error);
            });
    }
    catch(err){
        this.log.error(
            { error: err && err.message },
            'Error while communicating with FCM',
        );
    }
  }
}

另一个类.ts

import { Inject } from "@nestjs/common";
import { ChatService } from "src/chats/chat.service";
import * as _ from 'lodash';
import { CustomerPushEventHandler } from "src/chats/event-handlers/customer.push.handler";

 export class CustomerNotificationEventhandler {
   constructor(@Inject('Logger') private readonly log,
    private readonly chatService: ChatService,
    @Inject('CustomerNotificationConsumer') private readonly customerNotifConsumer,
   ) {
       this.handle();
    }

   async handle() {
        
      //Here I awant to access handle() method defined in CustomerPushEventHandler class 
   }
}

我怎样才能做到这一点？

【问题讨论】：

使CustomerPushEventHandler 可注入，并将此类添加到提供程序数组中。
你能显示代码吗？

标签： typescript nestjs

【解决方案1】：

您应该将 CustomerPushEventHandler 添加到 CustomerNotificationEventhandler 构造函数中。所以代码应该是这样的：

import { Inject } from "@nestjs/common";
import { ChatService } from "src/chats/chat.service";
import * as _ from 'lodash';
import { CustomerPushEventHandler } from "src/chats/event-handlers/customer.push.handler";

 export class CustomerNotificationEventhandler {
   constructor(@Inject('Logger') private readonly log,
    private readonly chatService: ChatService,
    @Inject('CustomerNotificationConsumer') private readonly customerNotifConsumer,
    private readonly customerPushEventHandler: CustomerPushEventHandler
   ) {
       this.handle();
    }

   async handle() {
        this.customerPushEventHandler.handle()
      //Here I awant to access handle() method defined in CustomerPushEventHandler class 
   }
}

【讨论】：

【解决方案2】：

首先，使CustomerPushEventHandler可注入

@Injectable()
export class CustomerPushEventHandler implements IEventHandler<CustomerPushEvent>{
    // class properties & methods
}

然后在模块的提供者数组中添加CustomerPushEventHandler

@Module({
    providers: [
        CustomerPushEventHandler
    ],
})
export class AppModule {
}

然后注入CustomerNotificationEventhandler

export class CustomerNotificationEventhandler {
    constructor( private readonly customerPushEventHandler: CustomerPushEventHandler
    ) {
    this.handle();
    }

    async handle() {
        // you need CustomerPushEvent object here to proceed further
        this.customerPushEventHandler.handle(customerEvent)
    }
}

【讨论】：