Call of object.method from event gets empty object

Mark_M

this is an alternative of 'wrapping' - .bind() :

const O = {
  a:"", b:0,
  m : function(){
    this.a = this.a + "*";
    this.b = this.b + 1;
    print(this.a," - ", this.b);
  }
};
var O_M = O.m.bind(O); // binding O as context for 'this' in function / method m
                      // returns a new function with the right context set of this for O.

setInterval(O_M,1000);

For Function.prototype.bind() see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_objects/Function/bind (and take also a look at the referenced .apply(...) ).

Btw, in JS same upper/lower/camel-casing as Java is useful. Constructor functions - like Classes in Java (and other 'like-minded' languages) - have an uppercase initial.