home.ts

import { Component } from '@angular/core';
import { Http } from '@angular/http';
import 'rxjs/add/operator/map';
@Component({
  templateUrl: 'build/pages/home/home.html'
})
export class HomePage {
  public items;
  constructor(
    public http: Http
  ) {

    this.http.get('/api/feed')
      .map(res => res.json())
      .subscribe(res => this.items = res);
  }

}

index.js

var express = require('express');
var app = express();

app.get('/api/feed', function(req, res) {
  res.json({
    name: 'feed',
    items: ['first', 'second']
  });
});

var server = app.listen(3000, function() {

  var host = server.address().address;
  var port = server.address().port;

  console.log('Example app listening at http://%s:%s', host, port);

});

ionic.config.json

{
  "name": "tmp",
  "app_id": "",
  "v2": true,
  "typescript": true,
  "proxies": [{
    "path": "/api",
    "proxyUrl": "http://0.0.0.0:3000/api"
  }]
}