Cannot read property 'prototype' of undefined in typescript

I am developing a Ionic2 project. I want to run inheritance class. There is a MyApp class in file app.ts. I am working other with a file. Another class of app.ts need to call the function.

export class AllPage extends MyApp {

  constructor(public app: App, public platform: Platform, public menu: MenuController) {

When I was run code take a error.

Cannot read property ‘prototype’ of undefined.

NOTE: There is openMenu() function in components MyApp. I want to run openMenu() function in components AllPage.

Thanks :slight_smile: