Object.getOwnPropertyDescriptors(O)

Object.getOwnPropertyDescriptors.md

Object.getOwnPropertyDescriptors(O)

When the getOwnPropertyDescriptors function is called, the following steps are taken:

1. Let obj be ToObject(O).
2. ReturnIfAbrupt(obj).
3. Let keys be the result of calling the [[OwnPropertyKeys]] internal method of obj.
4. ReturnIfAbrupt(keys).
5. Let descriptors be the result of the abstract operation ObjectCreate with the intrinsic object %ObjectPrototype% as its argument.
6. Let gotAllNames be false.
7. Repeat while gotAllNames is false, 1. Let next be the result of IteratorStep(keys). 1. ReturnIfAbrupt( next ). 1. If next is false, then let gotAllNames be true. 1. Else,
   1. Let nextKey be IteratorValue(next).
   2. Let nextKey be ToPropertyKey(nextKey).
   3. ReturnIfAbrupt(nextKey).
   4. Let desc be the result of calling the [[GetOwnProperty]] internal method of obj with argument nextKey.
   5. ReturnIfAbrupt(desc).
   6. Let descriptor be FromPropertyDescriptor(desc).
   7. ReturnIfAbrupt(descriptor).
   8. Let status be the result of CreateDataProperty(descriptors, nextKey, descriptor).
   9. Assert: status is not an abrupt completion.
8. Return descriptors.

Would you mind adding an example? I always find those tremendously helpful in proposals.

Shallow copy

let shallowCopy = Object.create(
  Object.getPrototypeOf(originalObject),
  Object.getOwnPropertyDescriptors(originalObject)
);

"Real" Mixins usable with classes prototypes too.

let mix = (object) => ({
  with: (...mixins) => mixins.reduce(
    (c, mixin) => Object.create(
      c, Object.getOwnPropertyDescriptors(mixin)
    ), object)
});

let a = {a: 'a'};
let b = {b: 'b'};
let c = {c: 'c'};
let d = mix(c).with(a, b);

Polluting

Object.defineProperties(
  target,
  Object.getOwnPropertyDescriptors(source)
);