title: TypeError: is not a function typescript class
body: <p>I'm getting the following error in my typescript class and cannot understand why. All I am doing is trying to call a helper function passing the token. </p>
  
  <p>Error:</p>
  
  <blockquote>
    <p>post error:  TypeError: this.storeToken is not a function(…)</p>
  </blockquote>
  
  <p>Class: </p>
  
  <pre class="lang-js prettyprint-override"><code>/**
   * Authentication Service:
   *
   * Contains the http request logic to authenticate the
   * user.
   */
  import { Injectable } from '@angular/core';
  import { Http, Response, Headers, RequestOptions } from '@angular/http';
  
  import 'rxjs/Rx';
  import { Observable } from 'rxjs/Observable';
  
  import { AuthToken } from './auth-token.service';
  
  import { User } from '../../shared/models/user.model';
  
  @Injectable()
  export class Authenticate {
  
    constructor(
      private http: Http,
      private authToken: AuthToken
    ) {}
  
    post(user: User): Observable&lt;any&gt; {
      let url = 'http://localhost:4000/';
      let body = JSON.stringify(user);
      let headers = new Headers({ 'content-type': 'application/json' });
      let options = new RequestOptions({ headers: headers });
  
      return this.http.post(url + 'login', body, options)
        .map(this.handleData)
        .catch(this.handleError);
    }
  
    private storeToken(token: string) {
      this.authToken.setToken(token);
    }
  
    private handleData(res: Response) {
      let body = res.json();
      this.storeToken(body.token);
      return body.fields || {};
    }
  
    private handleError(error: any) {
      console.error('post error: ', error);
      return Observable.throw(error.statusText);
    }
  }
  </code></pre>
  
  <p>I am new to typescript so I'm sure I am missing something ridiculously simple. Any assist would be great.</p>
  
  <p>Thanks.</p>