'use strict'; module.exports = function () { var symbol; if (typeof Symbol !== 'function') return false; symbol = Symbol('test symbol'); try { String(symbol); } catch (e) { return false; } if (typeof Symbol.iterator === 'symbol') return true; // Return 'true' for polyfills if (typeof Symbol.isConcatSpreadable !== 'object') return false; if (typeof Symbol.iterator !== 'object') return false; if (typeof Symbol.toPrimitive !== 'object') return false; if (typeof Symbol.toStringTag !== 'object') return false; if (typeof Symbol.unscopables !== 'object') return false; return true; };