Angular 订阅,如何让方法有订阅

Angular subscribe, how do I make a method have a subscription

我是 Angular 2 的新手,不知道如何进行订阅。 我有一个看起来像(简单版本)的会员服务:

import { Injectable, NgZone, Output, EventEmitter } from '@angular/core';
import { Network } from '@ionic-native/network';
import { HttpProvider } from '../providers/http-provider';

@Injectable()
export class Member {

  firstName:string = "";
  surname:string = "";

  constructor(private httpProvider: HttpProvider, private network: Network, zone: NgZone) {
  }

  createMember(member){
    this.httpProvider.createMember(member).subscribe(
      result => {
        var data = JSON.parse( result['_body'] );
        this.firstName = member.FirstName;
        this.surname = member.Surname;
        return true;
      },
      err =>{
        console.error("Error : "+err);
        return false;
      }
    );
  }
}

然后我有另一个使用会员服务的组件,我想要这样的东西:

this.member.createMember(member).subscribe(data)....

所以我可以检查成员是否已成功创建。

我会做这样的事情

组件

 this.membersService.createMember(member)
     .subscribe(res => {
         console.log('success', res)
        }, err => {
          console.log('error', err);
        });

服务

import {Injectable} from '@angular/core';
import {Http, RequestOptions, Response, Headers} from '@angular/http';
import 'rxjs/Rx';

  createMember(member) {
    const body = JSON.stringify(member);
    const headers = new Headers({
      'Content-Type': 'application/json'
    });
    const options = new RequestOptions({headers: headers});

    return this.http.post('/api/members', body, options)
      .map((res: Response) => res.json())
      .catch((err: any) => console.log(err));
  }