lodash/test/union-methods.spec.ts

import assert from 'node:assert';
import lodashStable from 'lodash';
import { _, args } from './utils';

describe('union methods', () => {
    lodashStable.each(['union', 'unionBy', 'unionWith'], (methodName) => {
        const func = _[methodName];

        it(`\`_.${methodName}\` should return the union of two arrays`, () => {
            const actual = func([2], [1, 2]);
            assert.deepStrictEqual(actual, [2, 1]);
        });

        it(`\`_.${methodName}\` should return the union of multiple arrays`, () => {
            const actual = func([2], [1, 2], [2, 3]);
            assert.deepStrictEqual(actual, [2, 1, 3]);
        });

        it(`\`_.${methodName}\` should not flatten nested arrays`, () => {
            const actual = func([1, 3, 2], [1, [5]], [2, [4]]);
            assert.deepStrictEqual(actual, [1, 3, 2, [5], [4]]);
        });

        it(`\`_.${methodName}\` should ignore values that are not arrays or \`arguments\` objects`, () => {
            const array = [0];
            assert.deepStrictEqual(func(array, 3, { '0': 1 }, null), array);
            assert.deepStrictEqual(func(null, array, null, [2, 1]), [0, 2, 1]);
            assert.deepStrictEqual(func(array, null, args, null), [0, 1, 2, 3]);
        });
    });
});