Variable Scope in Callback function in Class

Question

I read this question and this question. Both handle the variable scope in functions and not in classes where I can not make the that trick. How can I set a class variable in the callback method?

class A{
constructor(){
  this.name="";
}
callbackFunction(){
  this.name="abc"; //not working, this is undefined
}

loadComponents(){
 promise.then(this.callbackFunction);
}
}