3 var validTypes = { object: true, symbol: true };
5 module.exports = function () {
7 if (typeof Symbol !== 'function') return false;
8 symbol = Symbol('test symbol');
9 try { String(symbol); } catch (e) { return false; }
11 // Return 'true' also for polyfills
12 if (!validTypes[typeof Symbol.iterator]) return false;
13 if (!validTypes[typeof Symbol.toPrimitive]) return false;
14 if (!validTypes[typeof Symbol.toStringTag]) return false;