Problem with asynchronous code in class ES6

Hi !

class A {
	constructor(x, y){
	//class field...
	}

	AsyncFuncA(){
	//code...
	}

	run(){
	//call async code
		setInterval(() => {
	  		this.AsyncFuncA();
		}, 1000)
	}
}

class B {
	constructor(x, y){
		super(x,y);
	}

	AsyncFuncB(){
       //code...
	}

	run(){
	//call async code
		super.run();
		setInterval(() => {
	  	// Todo...
	  		this.AsyncFuncB();
		}, 2000);
	}
}
/**********************************************/
let ob = new B(x, y);
ob.run();

an error occurs when you call run() -> this.AsyncFuncA()
Web IDE:

"Uncaught Error: Function "AsyncFuncA" not found!
at line 248 col 6
this.AsyncFuncA();

  ^

in function called from system"

how can this be fought ?