lodash/test/isWeakMap.spec.ts

import assert from 'node:assert';
import lodashStable from 'lodash';
import { weakMap, falsey, stubFalse, args, slice, map, symbol, realm } from './utils';
import isWeakMap from '../src/isWeakMap';

describe('isWeakMap', () => {
    it('should return `true` for weak maps', () => {
        if (WeakMap) {
            assert.strictEqual(isWeakMap(weakMap), true);
        }
    });

    it('should return `false` for non weak maps', () => {
        const expected = lodashStable.map(falsey, stubFalse);

        const actual = lodashStable.map(falsey, (value, index) =>
            index ? isWeakMap(value) : isWeakMap(),
        );

        assert.deepStrictEqual(actual, expected);

        assert.strictEqual(isWeakMap(args), false);
        assert.strictEqual(isWeakMap([1, 2, 3]), false);
        assert.strictEqual(isWeakMap(true), false);
        assert.strictEqual(isWeakMap(new Date()), false);
        assert.strictEqual(isWeakMap(new Error()), false);
        assert.strictEqual(isWeakMap(slice), false);
        assert.strictEqual(isWeakMap({ a: 1 }), false);
        assert.strictEqual(isWeakMap(map), false);
        assert.strictEqual(isWeakMap(1), false);
        assert.strictEqual(isWeakMap(/x/), false);
        assert.strictEqual(isWeakMap('a'), false);
        assert.strictEqual(isWeakMap(symbol), false);
    });

    it('should work for objects with a non-function `constructor` (test in IE 11)', () => {
        const values = [false, true],
            expected = lodashStable.map(values, stubFalse);

        const actual = lodashStable.map(values, (value) => isWeakMap({ constructor: value }));

        assert.deepStrictEqual(actual, expected);
    });

    it('should work with weak maps from another realm', () => {
        if (realm.weakMap) {
            assert.strictEqual(isWeakMap(realm.weakMap), true);
        }
    });
});