import isObject from './isObject.js';
import { nativeKeys, hasEnumBug } from './_setup.js';
import has from './_has.js';
import collectNonEnumProps from './_collectNonEnumProps.js';

Retrieve the names of an object’s own properties. Delegates to ECMAScript 5‘s native Object.keys.

export default function keys(obj) {
  if (!isObject(obj)) return [];
  if (nativeKeys) return nativeKeys(obj);
  var keys = [];
  for (var key in obj) if (has(obj, key)) keys.push(key);

  if (hasEnumBug) collectNonEnumProps(obj, keys);
  return keys;
}