Add more methods to the array helper

[AhmedHdeawy]

Feat: Added exists and last methods to the array helper.

I wrote test cases as well for both.

[AhmedHdeawy]

@vinayak25 ??

[vinayak25]

Hi @AhmedHdeawy I will review it tomorrow and merge. Been super busy in some windows related bugs

Thanks!

[vikashviraj]

Suggested change

	static last<T = any>(
	arr: T[],
	predicate?: ((item: T, index: number, array: T[]) => boolean) | null
	): T | undefined {
	if (!arr || arr.length === 0) {
	return undefined;
	}
	if (!predicate) {
	return arr[arr.length - 1];
	}
	for (let i = arr.length - 1; i >= 0; i--) {
	if (predicate(arr[i], i, arr)) {
	return arr[i];
	}
	}
	return undefined;
	}
	static last<T>(arr: T[], predicate?: (item: T, index: number, array: T[]) => boolean): T | undefined {
	if (!arr || arr.length === 0) {
	return undefined;
	}
	if (!predicate) {
	return arr[arr.length - 1];
	}
	for (let i = arr.length - 1; i >= 0; i--) {
	if (predicate(arr[i], i, arr)) {
	return arr[i];
	}
	}
	return undefined;
	}

[vikashviraj]

Suggested change

	static exists<T = any>(arr: T[], key: string | number): boolean {
	if (typeof key === 'number' && key >= 0 && key < arr.length) {
	return true;
	}
	if (typeof key === 'string') {
	const splitKeys = key.split('.');
	if (!splitKeys.length) return false;
	if (Arr.isArray(arr[splitKeys[0]])) {
	return Arr.exists(arr[splitKeys[0]], splitKeys.slice(1).join('.'));
	}
	if (Obj.isObj(arr[splitKeys[0]])) {
	return Obj.get(arr[splitKeys[0]], splitKeys.slice(1).join('.')) !== undefined;
	}
	}
	return false;
	}
	static exists<T>(arr: T[], key: string | number): boolean {
	// If the key is a number, just check if it's a valid index.
	if (typeof key === 'number') {
	return key >= 0 && key < arr.length;
	}
	// If the key is a string, treat it as a path like "0.someKey.2"
	const splitKeys = key.split('.');
	// Early exit if no path given (e.g. empty string)
	if (splitKeys.length === 0 || (splitKeys.length === 1 && splitKeys[0] === '')) {
	return false;
	}
	let current: any = arr;
	for (let i = 0; i < splitKeys.length; i++) {
	let currentKey = splitKeys[i];
	// Check if currentKey should be an array index
	const isIndex = !isNaN(parseInt(currentKey));
	if (Array.isArray(current)) {
	if (!isIndex) {
	// The path expects a number index, but got a string that isn't a number
	return false;
	}
	const idx = parseInt(currentKey, 10);
	if (idx < 0 || idx >= current.length) {
	return false;
	}
	current = current[idx];
	} else if (current !== null && typeof current === 'object') {
	// For objects, currentKey must be a string property
	if (!(currentKey in current)) {
	return false;
	}
	current = current[currentKey];
	} else {
	// current is neither an array nor an object; no further traversal possible
	return false;
	}
	}
	// If we've navigated the entire path without issues, it exists
	return true;
	}

[vikashviraj]

Suggested change

	describe('Array Helper', () => {
	beforeEach(async () => { });
	it('check key exists', () => {
	const arr = [1, 2, 3, 4, 5];
	expect(Arr.exists(arr, 2)).toBeTruthy();
	});
	it('check key does not exist', () => {
	const arr = [1, 2, 3, 4, 5];
	expect(Arr.exists(arr, 6)).toBeFalsy();
	});
	it('should return last element matching predicate', () => {
	const arr = [1, 2, 3, 4, 5];
	expect(Arr.last(arr, x => x < 4)).toBe(3);
	expect(Arr.last(arr)).toBe(5);
	});
	it('should return the last object that matches the predicate', () => {
	const users = [
	{ name: 'Alice', age: 25 },
	{ name: 'Bob', age: 30 },
	{ name: 'Charlie', age: 35 },
	{ name: 'David', age: 30 }
	];
	const lastUserUnder35 = Arr.last(users, user => user.age < 35);
	expect(lastUserUnder35).toEqual({ name: 'David', age: 30 });
	});
	it('should return undefined for empty array', () => {
	expect(Arr.last([])).toBeUndefined();
	});
	});
	describe('Arr Utility Class', () => {
	describe('Arr.exists', () => {
	const sampleArray = [1, 2, { name: 'Alice', friends: ['Bob', 'Carol'] }];
	const arr = [1, 2, 3, 4, 5];
	it('check key exists', () => {
	expect(Arr.exists(arr, 2)).toBeTruthy();
	});
	it('check key does not exist', () => {
	expect(Arr.exists(arr, 6)).toBeFalsy();
	});
	it('should return true for a valid index (0)', () => {
	expect(Arr.exists(sampleArray, 0)).toBe(true);
	});
	it('should return true for a nested property ("2.name")', () => {
	expect(Arr.exists(sampleArray, '2.name')).toBe(true);
	});
	it('should return true for a deeper nested array property ("2.friends.1")', () => {
	expect(Arr.exists(sampleArray, '2.friends.1')).toBe(true);
	});
	it('should return false for a non-existent property ("2.age")', () => {
	expect(Arr.exists(sampleArray, '2.age')).toBe(false);
	});
	});
	describe('Arr.last', () => {
	it('should return last element matching predicate', () => {
	const arr = [1, 2, 3, 4, 5];
	expect(Arr.last(arr, x => x < 4)).toBe(3);
	expect(Arr.last(arr)).toBe(5);
	});
	it('should return the last object that matches the predicate', () => {
	const users = [
	{ name: 'Alice', age: 25 },
	{ name: 'Bob', age: 30 },
	{ name: 'Charlie', age: 35 },
	{ name: 'David', age: 30 },
	];
	const lastUserUnder35 = Arr.last(users, user => user.age < 35);
	expect(lastUserUnder35).toEqual({ name: 'David', age: 30 });
	});
	it('should return undefined for empty array', () => {
	expect(Arr.last([])).toBeUndefined();
	});
	});
	});

[vikashviraj]

Many thanks, @AhmedHdeawy, for your contribution. I just added a few suggestions. If they look good, feel free to accept them.

FYI: @vinayak25

[AhmedHdeawy]

Many thanks, @AhmedHdeawy, for your contribution. I just added a few suggestions. If they look good, feel free to accept them.

FYI: @vinayak25

Hi @vikashviraj

thanks for your contribution.

Could you please clarify the reasoning behind the changes, especially the additions to the exists method? I'm unsure of their necessity and would appreciate a better understanding of their purpose.

[AhmedHdeawy]

@vinayak25 Have you reviewed it?

[AhmedHdeawy]

Hi @vinayak25

I've updated the code and fixed all linting issues.