WeakMap VS root classes

wm-inheritance.js

WeakMap.prototype.hasInherited = function hasInherited(obj) {
  let found = false;
  while (obj && obj !== Object.prototype && !(found = this.has(obj)))
    obj = Object.getPrototypeOf(obj);
  return found;
};

WeakMap.prototype.setInherited = function setInherited(obj, value) {
  let ref = obj;
  while (ref && ref !== Object.prototype) {
    const next = Object.getPrototypeOf(ref);
    if (!next || next === Object.prototype) {
      this.set(ref, value);
      break;
    }
    ref = next;
  }
  return obj;
};

WeakMap.prototype.getInherited = function getInherited(obj) {
  while (obj && !this.has(obj))
    obj = Object.getPrototypeOf(obj);
  return obj ? this.get(obj) : void 0;
};

// Test Case
class Test {}

const wm = new WeakMap;
const a = new Test;

console.assert(!wm.hasInherited(a), 'wm should not know a');

console.assert(wm.setInherited(a, Math.random()) === a, 'wm should return initial object');

console.assert(wm.hasInherited(a), 'wm should know a');

const b = new Test;

console.assert(wm.hasInherited(b), 'wm should know b');
console.assert(wm.getInherited(a) === wm.getInherited(b), 'wm should return same known value');