Why TypeScirpt class property undefined

Question

I have following code:-

class FeedbackController {

  public homePage(req, res){
    this.test();
    res.send('Welcome to feedback service');
  }
 
  private test(){
    console.log('test called');
  }
}

export default new FeedbackController();

This is how it is called:-

import FeedbackController from '../controller/feedbackController';

    const routes = (app) => {
        app.route('/')
        .get(FeedbackController.homePage);

    };

    export default routes;

I get error :-

TypeError: Cannot read property 'test' of undefined

What is wrong

Does this answer your question? [How to access the correct \`this\` inside a callback?](https://stackoverflow.com/questions/20279484/how-to-access-the-correct-this-inside-a-callback) — CertainPerformance, Mar 14 '21 at 05:32

Voskanyan David · Accepted Answer · 2021-03-14T06:23:07.853

0

This is not a TS problem, check how this works in JS here.

As a solution replace routes with

.get((req, res) => FeedbackController.homePage(req, res))

or

.get(FeedbackController.homePage.bind(FeedbackController))

edited Mar 14 '21 at 06:23

answered Mar 14 '21 at 06:16

Voskanyan David

987
6
6

added missing arguments – Voskanyan David Mar 14 '21 at 06:23

Why TypeScirpt class property undefined

1 Answers1