Issue with post a json

Ionic Framework
1

[ sorry for bad english ] hi i want send a json to mysql but i get these error.

ERROR SyntaxError: Unexpected end of JSON input
    at JSON.parse (<anonymous>)
    at Response.Body.json (http.js:1091)
    at SafeSubscriber._next (apis.ts:21)
    at SafeSubscriber.__tryOrUnsub (Subscriber.js:242)
    at SafeSubscriber.next (Subscriber.js:189)
    at Subscriber._next (Subscriber.js:129)
    at Subscriber.next (Subscriber.js:93)
    at XMLHttpRequest.onLoad (http.js:1591)
    at t.invokeTask (polyfills.js:3)
    at Object.onInvokeTask (core.js:4751)

my provider

import { Http,Response,Headers } from '@angular/http';
.
.
.
private urlsendnote:string="http://localhost/masterfinder_api/public/addnote";
.
.
.
  addNote(credentials) {
    return new Promise((resolve, reject) => {
      let headers = new Headers();
      this.http.post(this.urlsendnote, JSON.stringify(credentials), { headers: headers })
        .subscribe(res => {
          resolve(res.json());
        }), (err) => {
          reject(err);
        }
    });
  }

and this is my page.ts

import { ApisProvider } from '../../providers/apis/apis';
.
.
.
resposeData:any;
data={"t_id": "", "m_id": "", "note": ""};
this.data.note = 'testionic';
this.data.m_id = '1';
this.data.t_id ='1';
this.apis.addNote(this.data)