lodash/test/zipWith.spec.ts

import assert from 'node:assert';
import lodashStable from 'lodash';
import { slice } from './utils';
import zipWith from '../src/zipWith';
import zip from '../src/zip';

describe('zipWith', () => {
    it('should zip arrays combining grouped elements with `iteratee`', () => {
        const array1 = [1, 2, 3],
            array2 = [4, 5, 6],
            array3 = [7, 8, 9];

        var actual = zipWith(array1, array2, array3, (a, b, c) => a + b + c);

        assert.deepStrictEqual(actual, [12, 15, 18]);

        var actual = zipWith(array1, [], (a, b) => a + (b || 0));

        assert.deepStrictEqual(actual, [1, 2, 3]);
    });

    it('should provide correct `iteratee` arguments', () => {
        let args;

        zipWith([1, 2], [3, 4], [5, 6], function () {
            args || (args = slice.call(arguments));
        });

        assert.deepStrictEqual(args, [1, 3, 5]);
    });

    it('should perform a basic zip when `iteratee` is nullish', () => {
        const array1 = [1, 2],
            array2 = [3, 4],
            values = [, null, undefined],
            expected = lodashStable.map(values, lodashStable.constant(zip(array1, array2)));

        const actual = lodashStable.map(values, (value, index) =>
            index ? zipWith(array1, array2, value) : zipWith(array1, array2),
        );

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