symbols.js
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symbols.js
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	import { test, summary } from './helpers.js';

	console.log('Symbol Tests\n');

	const sym1 = Symbol('test');
	test('symbol typeof', typeof sym1, 'symbol');

	const sym2 = Symbol('test');
	test('symbols are unique', sym1 !== sym2, true);

	test('symbol description', sym1.description, 'test');

	const sym3 = Symbol();
	test('symbol without description', sym3.description, undefined);

	const obj = {};
	const symKey = Symbol('key');
	obj[symKey] = 'value';
	test('symbol as key', obj[symKey], 'value');

	const symFor1 = Symbol.for('shared');
	const symFor2 = Symbol.for('shared');
	test('Symbol.for same', symFor1 === symFor2, true);

	test('Symbol.keyFor', Symbol.keyFor(symFor1), 'shared');
	test('Symbol.keyFor local', Symbol.keyFor(sym1), undefined);

	test('Symbol.iterator exists', typeof Symbol.iterator, 'symbol');
	test('Symbol.toStringTag exists', typeof Symbol.toStringTag, 'symbol');
	test('Symbol.hasInstance exists', typeof Symbol.hasInstance, 'symbol');

	const custom = { [Symbol.toStringTag]: 'MyCustomType' };
	test('Symbol.toStringTag custom', Object.prototype.toString.call(custom), '[object MyCustomType]');

	summary();

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