Angular 2如何从嵌套的promise中返回对象数组 [英] Angular 2 how to return array of objects from nested promise

问题描述

我正在尝试编写服务以获取客户列表，但我不知道从嵌套的promose返回客户列表。

I am trying to write an service to get the list of customers but i don't know to return the list of customers from nested promose.

请帮助我提前谢谢。

import { Injectable } from '@angular/core';
import { SQLite } from 'ionic-native';

@Injectable()
export class CustomerService {
    private sDBName:string;
    private db;
    private isDBExist:boolean = false;

    constructor() {}

    setDBName(sDBName:string) {
        this.sDBName = sDBName;
    }

    connect():Promise<any> {        
        this.db = new SQLite();
        return this.db.openDatabase({
            name: this.sDBName,
            location: 'default'
        });
    }
    getCustomersList():Promise<any> {
        return Promise.resolve(()=>{            
            return this.connect().then(()=>{                
                this.isDBExist = true;
                let sql = 'SELECT * FROM customer ORDER BY customer_id DESC LIMIT 10';
                return this.db.executeSql(sql, {}).then((result)=>{ 
                    let customers = [];             
                    for(let i=0; i<result.rows.length; i++) {
                        customers.push(result.rows.item(i));
                    }
                    return customers;
                },(err)=>{
                    this.debug('Unable to select customers', err);
                    return [];
                });
            },(err)=>{
                this.debug('Unable to open database', err);
                return [];
            });
        });
    }
}

推荐答案

你我需要用 .then（...）来锁定电话。比如

You need to chain the call with .then(...) like

this.getCustomerList().then(result => this.myArray = result);

这篇关于Angular 2如何从嵌套的promise中返回对象数组的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！