async_await.ts

import { Component } from '@angular/core';
import { NavController } from 'ionic-angular';

@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage {

  constructor(
    public navCtrl: NavController
  ) {
    console.log('start')

    /****************
     * call C()
     ****************/
    c()
    function d() {
      return new Promise((resolve, reject) => {
        setTimeout(() =>{
          resolve('success')
        }, 5000)
      })
    }
    
    async function c() {
      let re = await d()
      console.log('re =', re)
    }

  }

  ionViewDidLoad() {

  /****************
   * call a()
   ****************/
   this.a();
    let i = 0
    setInterval(() =>{
      i++
      console.log('second =', i)
    }, 1000)
  }

  b() {
    return new Promise((resolve, reject) => {
      setTimeout(() =>{
        resolve('success')
      }, 5000)
    })
  }

  async a() {
    let re = await this.b()
    console.log('re =', re)
  }
}