3 var toString = Object.prototype.toString
4 , toStringTag = require('./').toStringTag
6 , id = '[object Symbol]'
7 , Global = (typeof Symbol === 'undefined') ? null : Symbol;
9 module.exports = function (x) {
10 return (x && ((Global && (x instanceof Global)) ||
11 (toString.call(x) === id) || (x[toStringTag] === 'Symbol'))) || false;