Sindbad~EG File Manager

"use strict";

var global     = require("ext/global-this")
  , validTypes = { object: true, symbol: true };

module.exports = function () {
	var Symbol = global.Symbol;
	var symbol;
	if (typeof Symbol !== "function") return false;
	symbol = Symbol("test symbol");
	try { String(symbol); }
	catch (e) { return false; }

	// Return 'true' also for polyfills
	if (!validTypes[typeof Symbol.iterator]) return false;
	if (!validTypes[typeof Symbol.toPrimitive]) return false;
	if (!validTypes[typeof Symbol.toStringTag]) return false;

	return true;
};