Access method of specific ancestor

Question

I'm currently trying to access the method of a specific ancestor in my dependency chain. Specifically, I want to run ParentClass.logName() from my initialized GrandChildClass. This is how I access the ParentClass prototype (approach taken from Get parent class name from child with ES6? ).

 class AncestorClass { constructor (name, id){ this.name = name + id; } logName () { console.log(this.name); } } class ParentClass extends AncestorClass { constructor (name, id) { super(name, 1); this.name = name + id; } } class ChildClass extends ParentClass { constructor (name, id) { super(name, 2); this.name = name + id; } } class GrandchildClass extends ChildClass { constructor (name, id){ super(name, 3); this.name = name + id; } } const grandchild = new GrandchildClass('testName', 4); const parent = Object.getPrototypeOf((Object.getPrototypeOf(grandchild.constructor))); console.log(parent); const initParent = new parent(); initParent.logName(); 

So I got the prototype and initialized it with the new keyword but for some reason initParent.logName() returns NaN.

So how do I call to ParentClass.logName from my grandchild without initializing ParentClass directly?

Answer 1

You initialize parent with an empty constructor, which means both attribute are undefined and undefined + undefined gives NaN .

const initParent = new parent('foo', 1);
initParent.logName() // print 'foo1'

 class AncestorClass { constructor (name, id){ this.name = name + id; } logName () { console.log(this.name); } } class ParentClass extends AncestorClass { constructor (name, id) { super(name, 1); this.name = name + id; } } class ChildClass extends ParentClass { constructor (name, id) { super(name, 2); this.name = name + id; } } class GrandchildClass extends ChildClass { constructor (name, id){ super(name, 3); this.name = name + id; } } const grandchild = new GrandchildClass('testName', 4); const parent = Object.getPrototypeOf((Object.getPrototypeOf(grandchild.constructor))); console.log(parent); const initParent = new parent('foo', 1); initParent.logName();