$.set-proto.js

// Works with __proto__ only. Old v8 can't work with null proto objects.
/* eslint-disable no-proto */
var getDesc  = require('./$').getDesc
  , isObject = require('./$.is-object')
  , anObject = require('./$.an-object');
var check = function(O, proto){
  anObject(O);
  if(!isObject(proto) && proto !== null)throw TypeError(proto + ": can't set as prototype!");
};
module.exports = {
  set: Object.setPrototypeOf || ('__proto__' in {} ? // eslint-disable-line
    function(test, buggy, set){
      try {
        set = require('./$.ctx')(Function.call, getDesc(Object.prototype, '__proto__').set, 2);
        set(test, []);
        buggy = !(test instanceof Array);
      } catch(e){ buggy = true; }
      return function setPrototypeOf(O, proto){
        check(O, proto);
        if(buggy)O.__proto__ = proto;
        else set(O, proto);
        return O;
      };
    }({}, false) : undefined),
  check: check
};