AI solution for JavaScript Coding Question on BFE.dev
27. implement completeAssign()

One possible solution to the problem is:

function completeAssign(target, ...sources) {
  sources.forEach(source => {
    Object.getOwnPropertyNames(source).forEach(prop => {
      const descriptor = Object.getOwnPropertyDescriptor(source, prop);
      Object.defineProperty(target, prop, descriptor);
    });
    Object.getOwnPropertySymbols(source).forEach(sym => {
      const descriptor = Object.getOwnPropertyDescriptor(source, sym);
      Object.defineProperty(target, sym, descriptor);
    });
  });
  return target;
}

This implementation uses Object.getOwnPropertyNames() and Object.getOwnPropertySymbols() to loop through all the own properties of each source object, and then uses Object.defineProperty() to copy the descriptors to the target object. This way, all the data descriptors (both enumerable and non-enumerable) as well as accessor descriptors (both enumerable and non-enumerable) are copied correctly.

To use the function, you can call it like this:

const result = completeAssign({}, source);

This will create an empty object as the target, and copy all the properties (including descriptors) of source to it. Note that the completeAssign() function modifies the first argument (target) in place and returns it, just like Object.assign().