lodash/test/size.spec.js

import lodashStable from 'lodash';
import { falsey, stubZero, args, push, arrayProto, realm, MAX_SAFE_INTEGER } from './utils';
import size from '../src/size';

describe('size', () => {
    const array = [1, 2, 3];

    it('should return the number of own enumerable string keyed properties of an object', () => {
        expect(size({ one: 1, two: 2, three: 3 })).toBe(3);
    });

    it('should return the length of an array', () => {
        expect(size(array)).toBe(3);
    });

    it('should accept a falsey `object`', () => {
        const expected = lodashStable.map(falsey, stubZero);

        const actual = lodashStable.map(falsey, (object, index) => {
            try {
                return index ? size(object) : size();
            } catch (e) {}
        });

        expect(actual).toEqual(expected);
    });

    it('should work with `arguments` objects', () => {
        expect(size(args)).toBe(3);
    });

    it('should work with jQuery/MooTools DOM query collections', () => {
        function Foo(elements) {
            push.apply(this, elements);
        }
        Foo.prototype = { length: 0, splice: arrayProto.splice };

        expect(size(new Foo(array))).toBe(3);
    });

    it('should work with maps', () => {
        if (Map) {
            lodashStable.each([new Map(), realm.map], (map) => {
                map.set('a', 1);
                map.set('b', 2);
                expect(size(map)).toBe(2);
                map.clear();
            });
        }
    });

    it('should work with sets', () => {
        if (Set) {
            lodashStable.each([new Set(), realm.set], (set) => {
                set.add(1);
                set.add(2);
                expect(size(set)).toBe(2);
                set.clear();
            });
        }
    });

    it('should not treat objects with negative lengths as array-like', () => {
        expect(size({ length: -1 })).toBe(1);
    });

    it('should not treat objects with lengths larger than `MAX_SAFE_INTEGER` as array-like', () => {
        expect(size({ length: MAX_SAFE_INTEGER + 1 })).toBe(1);
    });

    it('should not treat objects with non-number lengths as array-like', () => {
        expect(size({ length: '0' })).toBe(1);
    });
});