Ionic Storage delivers undefined value
<p>How I can use the Ionic Storage within my application. I tried with the following, but when I try to read out I get always <code>[object Object]</code> as value back. It works when I have the get/set method in one class, but I want structure my project and outsource the storage part.</p>

<pre><code>@Component({
      selector: 'page-login',
      templateUrl: 'login.html'
    })
    export class LoginPage {

      constructor(public testData: TestData) {}

      onLogin(form) { 

        if (form.valid) {
          this.testData.setTestParam("abc");
          console.log("Stored: " +   this.testData.getTestParam()) ;
          // delivers =&gt; Stored: [object Object]
        }
    }    
</code></pre>

<p><strong>TestData Class</strong></p>

<pre><code>@Injectable()
export class TestData {

 constructor(public storage : Storage) {}

 setTestParam(testparam) 
 {
   this.storage.set('test_param', testparam);
 }

 getTestParam(){
   return this.storage.get('test_param').then((value) =&gt; {
      return value;
   });
 }
}
</code></pre>