import lodashStable from 'lodash'; import { symbol, falsey, stubFalse, args, slice, realm } from './utils'; import isSymbol from '../src/isSymbol'; describe('isSymbol', () => { it('should return `true` for symbols', () => { if (Symbol) { expect(isSymbol(symbol)).toBe(true); expect(isSymbol(Object(symbol))).toBe(true); } }); it('should return `false` for non-symbols', () => { const expected = lodashStable.map(falsey, stubFalse); const actual = lodashStable.map(falsey, (value, index) => index ? isSymbol(value) : isSymbol(), ); expect(actual).toEqual(expected); expect(isSymbol(args)).toBe(false); expect(isSymbol([1, 2, 3])).toBe(false); expect(isSymbol(true)).toBe(false); expect(isSymbol(new Date())).toBe(false); expect(isSymbol(new Error())).toBe(false); expect(isSymbol(slice)).toBe(false); expect(isSymbol({ 0: 1, length: 1 })).toBe(false); expect(isSymbol(1)).toBe(false); expect(isSymbol(/x/)).toBe(false); expect(isSymbol('a')).toBe(false); }); it('should work with symbols from another realm', () => { if (Symbol && realm.symbol) { expect(isSymbol(realm.symbol)).toBe(true); } }); });