与奥雷利亚的继承

Question

Hi I am using Aurelia with Visual studio 2015.

I am creating a sports data related site.

Here I am having a base class which fetches basic details regarding the sports event. I inherit this base class from another class and fetch more information based on the base class property value.

Here is my base class --

import {inject} from 'aurelia-framework';
import {SportsEventService} from '../services/data-services/sports-event-service.js';

@inject(SportsEventService)
export class BaseClass{
    sportsEvent;

    constructor(sportsEventService){
        this.SportsEventService = sportsEventService;        
    }

    getSportsEventDetail(sportsEventName){              
        return this.SportsEventService.getSportsEventDetail(sportsEventName)
             .then(response => {                 
                 this.sportsEvent = response;                                  
                 return this.sportsEvent;                 
             });    
    }    
}

Here is my child class which inherits base class -

import {inject} from 'aurelia-framework';
import {SportsEventService} from '../services/data-services/sports-event-service.js';
import {SportsEvent} from './sports-event'

@inject(SportsEventService)
export class ChildClass extends BaseClass{
    constructor(sportsEventService){
        super(sportsEventService);        
    }

    getUpcomingFixture(){                 
        return (this.UpcomingFixtureService.getUpcomingFixture(this.sportsEvent.leagueId)
                .then(response => {                     
                    return response; 
                }));
    }
}

Here, when I am using baseClass property, "this.sportsEvent" it is giving me "Undefine". Can anybody tell me, how can I make this work?

Answer 1

this.sportsEvent will be undefined until it's assigned at the this.sportsEvent = response; line.

You won't be able to call the ChildClass.getUpcomingFixture method until the base class's getSportsEventDetail method has finished because ChildClass.getUpcomingFixture depends on this.sportsEvent .

Try executing the code like this:

childClass.getSportsEventDetail(sportsEventName)
  .then(() => childClass.getUpcomingFixture());