梁美英 / programming · Files

// 19.1.2.9 / 15.2.3.2 Object.getPrototypeOf(O)
var has         = require('./_has')
  , toObject    = require('./_to-object')
  , IE_PROTO    = require('./_shared-key')('IE_PROTO')
  , ObjectProto = Object.prototype;

module.exports = Object.getPrototypeOf || function(O){
  O = toObject(O);
  if(has(O, IE_PROTO))return O[IE_PROTO];
  if(typeof O.constructor == 'function' && O instanceof O.constructor){
    return O.constructor.prototype;
  } return O instanceof Object ? ObjectProto : null;
};