home.ts

import {Page} from 'ionic-framework/ionic';

@Page({
  template: `
  <ion-navbar *navbar>
  <ion-title>
    Home
  </ion-title>
</ion-navbar>

<ion-content class="home">
  <ion-list>
    <ion-item-group *ngFor="#key of keys()">
      <ion-item-divider light>
        {{key}}
      </ion-item-divider>
      <ion-item *ngFor="#obj of data[key]">
        <pre>{{obj.first_name }}</pre>
      </ion-item>
    </ion-item-group>
  </ion-list>
</ion-content>

`,
})
export class HomePage {
  data = {
    "A": [
      {
        "first_name": "Albert"
      }
    ],
    "B": [
      {
        "first_name": "Ben"
      }
    ]
  }
  constructor() { }
  keys() {
    return Object.keys(this.data;
  }
}