How to find symetric differencebetween several array using filter and reduce?

[alamenai]

Steps to reproduce:

Targeted file: difference. js

Description:

The goal of this function is to find the asymmetric difference between two or more arrays. However, I found a silent bug when I was adding more unit tests.

Current implementation

export const difference = (...arrays) => {
    if (arrays.length === 1) return arrays[0]
    const args = Array.from([...arrays])
    let initArray = args[0];
    let differentElements = new Set();
    args.forEach(array => args.indexOf(array) !== 0 && isArray(array) &&
        array.forEach(value => !initArray.includes(value) && differentElements.add(value)))
    return Array.from(differentElements)
}

New implementation

export const diff = (arr1, arr2) => {
	return [
		...arr1.filter((item) => !arr2.includes(item)),
		...arr2.filter((item) => !arr1.includes(item)),
	];
};

Expected failed tests:

	it('should return an array with the uncommon elements between arrays ', () => {

               expect(diff([1, 2], [1, 2, 5])).toStrictEqual([5]); // passed

		expect(diff([1, 2], [1, 2, 3], [1, 2, 3, 4])).toStrictEqual([4]); // failed

		expect(diff(['a', 'b'], ['b', 'a'], ['a', 'b', 'c'])).toStrictEqual(['c']); // failed

		expect(diff([null], [undefined, null], [undefined, null, 'Ala'])).toStrictEqual(['Ala']); //failed

		expect(diff(['diorite', 'andesite', 'grass', 'dirt', 'pink wool', 'dead shrub'],['diorite', 'andesite', 'grass', 'dirt', 'dead shrub'])
		).toStrictEqual(['pink wool']); // failed
	});

	it('should return an empty array ', () => {
		expect(diff([1, 2], [1, 2], [1, 2])).toStrictEqual([]); //failed
	});

	it('should return the original array ', () => {
		expect(diff([1, 2])).toStrictEqual([1, 2]); //failed
	});

[alamenai]

Solved : StackOverFlow Answer.