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- 'use strict';
- /* eslint complexity: [2, 17], max-statements: [2, 33] */
- module.exports = function hasSymbols() {
- if (typeof Symbol !== 'function' || typeof Object.getOwnPropertySymbols !== 'function') { return false; }
- if (typeof Symbol.iterator === 'symbol') { return true; }
- var obj = {};
- var sym = Symbol('test');
- var symObj = Object(sym);
- if (typeof sym === 'string') { return false; }
- if (Object.prototype.toString.call(sym) !== '[object Symbol]') { return false; }
- if (Object.prototype.toString.call(symObj) !== '[object Symbol]') { return false; }
- // temp disabled per https://github.com/ljharb/object.assign/issues/17
- // if (sym instanceof Symbol) { return false; }
- // temp disabled per https://github.com/WebReflection/get-own-property-symbols/issues/4
- // if (!(symObj instanceof Symbol)) { return false; }
- // if (typeof Symbol.prototype.toString !== 'function') { return false; }
- // if (String(sym) !== Symbol.prototype.toString.call(sym)) { return false; }
- var symVal = 42;
- obj[sym] = symVal;
- for (sym in obj) { return false; } // eslint-disable-line no-restricted-syntax
- if (typeof Object.keys === 'function' && Object.keys(obj).length !== 0) { return false; }
- if (typeof Object.getOwnPropertyNames === 'function' && Object.getOwnPropertyNames(obj).length !== 0) { return false; }
- var syms = Object.getOwnPropertySymbols(obj);
- if (syms.length !== 1 || syms[0] !== sym) { return false; }
- if (!Object.prototype.propertyIsEnumerable.call(obj, sym)) { return false; }
- if (typeof Object.getOwnPropertyDescriptor === 'function') {
- var descriptor = Object.getOwnPropertyDescriptor(obj, sym);
- if (descriptor.value !== symVal || descriptor.enumerable !== true) { return false; }
- }
- return true;
- };
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