Get parent class name from child with ES6?

Question

I would like to get the parent class name (Parent), but I\'m only able to retrieve the child class name with this code (Child)...

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Answer 1

From proto property:

Child['__proto__'].name

example here: https://stackblitz.com/edit/typescript-s5brk9

Answer 2

You could technically do

// instanceProto === Child.prototype
var instanceProto = Object.getPrototypeOf(instance);

// parentProto === Parent.prototype
var parentProto = Object.getPrototypeOf(instanceProto);
console.log(parentProto.constructor.name);

keep in mind that these names may all be mangled by minifiers.

Answer 3

ES6 classes inherit from each other. So when instance.constructor refers to the Child, then you can use Object.getPrototypeOf(instance.constructor) to get the Parent, and then access .name:

Object.getPrototypeOf(instance.constructor).name // == "Parent"

Of course, full ES6 compliance and non-minified code are necessary for this to work. You should never rely on function names in code.

Answer 4

Here is something amusing:

class J {}
    
class K extends J {}

class L extends K {}

function getBaseClass(targetClass){
  if(targetClass instanceof Function){
    let baseClass = targetClass;

    while (baseClass){
      const newBaseClass = Object.getPrototypeOf(baseClass);

      if(newBaseClass && newBaseClass !== Object && newBaseClass.name){
        baseClass = newBaseClass;
      }else{
        break;
      }
    }

    return baseClass;
  }
}

console.log(getBaseClass(L)); // Will return J.