feat: add intersection, union, complement, fullIntersection, array utility methods

src/modules/esl-utils/misc/array.ts

@@ -29,13 +29,44 @@ export const uniq = <T> (arr: T[]): T[] => {
   return result;
 };
 
-/** Crete an array filled with the range [0,..,N-1] */
+/** Create an array filled with the range [0,..,N-1] */
 export function range(n: number): number[];
-/** Crete an array filled with values returned by the filler callback */
+/** Create an array filled with values returned by the filler callback */
 export function range<T>(n: number, filler: (i: number) => T): T[];
 export function range(n: number, filler: (i: number) => any = identity): any[] {
   const arr = Array(n);
   let i = 0;
   while (i < n) arr[i] = filler(i++);
   return arr;
 }
+
+/** Create an array of unique values that presented in each of the passed arrays */
+export function intersection<T>(...rest: T[][]): T[];
+export function intersection(a: any[], b: any[], ...rest: any[][]): any[] {
+  if (rest.length) return intersection(a, intersection(b, ...rest));
+  return a.filter(Set.prototype.has, new Set(b));
+}
+
+/** Create an array with the unique values from each of the passed arays */
+export function union(...rest: any[][]): any[] {
+  const set = new Set();
+  rest.forEach(item => item.forEach(i => set.add(i)));
+  const result: any[] = [];
+  set.forEach(value => result.push(value));
+  return result;
+}
+
+/** Creates an array of unique values from the first array that are not present in the other arrays */
+export function complement<T>(...rest: T[][]): T[];
+export function complement(a: any[], b: any[], ...rest: any[][]): any[] {
+  if (rest.length > 1) return complement(a, complement(b, rest));
+  const setB = new Set(b);
+  return a.filter(element => !setB.has(element));
+}
+
+
+/** Check for elements from array B in array A */
+export function fullIntersection(a: any[], b: any[]): boolean {
+  const setA = new Set(a);
+  return a.length === 0 && b.length === 0 ? true : !b.filter((item: any) => !setA.has(item)).length;
+}

src/modules/esl-utils/misc/test/array.test.ts

@@ -1,4 +1,4 @@
-import {flat, range, tuple, uniq, wrap} from '../array';
+import {flat, range, tuple, uniq, wrap, intersection, union, complement, fullIntersection} from '../array';
 
 describe('misc/array helper tests', () => {
   test('tuple', () => {
@@ -45,3 +45,40 @@ describe('misc/array helper tests', () => {
     expect(range(9, (x) => x / 8)).toEqual([...Array(9).keys()].map((x) => x / 8))
   });
 });
+
+test('intersection', () => {
+  const a = {a: 3};
+  expect(intersection([],[])).toEqual([]);
+  expect(intersection([1],[1])).toEqual([1]);
+  expect(intersection([1, 2, 3], [1, 2], [1, 2, 4])).toEqual([1, 2]);
+  expect(intersection([1, [2, 3], a], [a, 1, [2, 3]])).toEqual([1, a]);
+  expect(intersection([null, 1, 2, 3, [6]], [4, 5])).toEqual([]);
+  expect(intersection([1, 2, 3, [6]], [4, 5, 1, 2], [1])).toEqual([1]);
+});
+
+test('union', () => {
+  const a = {a:3};
+  expect(union([], [])).toEqual([]);
+  expect(union([1], [1])).toEqual([1]);
+  expect(union([1, 2], [1, 2], [1, 2])).toEqual([1, 2,]);
+  expect(union([1, [2, 3], a], [a, 1, [2, 3]])).toEqual([1, [2, 3], a, [2, 3]]);
+  expect(union([1, 2, 3, null, [6]], [4, 5], [1, 2, 3, null, [6]], [4, 5])).toEqual([1, 2, 3, null, [6], 4, 5, [6]]);
+});
+
+test('complement', () => {
+  const a = {a: 3};
+  expect(complement([],[])).toEqual([]);
+  expect(complement([1],[1])).toEqual([]);
+  expect(complement([1, 2, 3], [1, 2], [1, 2, 5])).toEqual([3]);
+  expect(complement([1, [2, 3], a], [a, 1, [2, 3]])).toEqual([[2, 3]]);
+  expect(complement([null, 1, 2, 3, null, [6]], [4, 5])).toEqual([null, 1, 2, 3, null, [6]]);
+});
+
+test('fullIntersection', () => {
+  const a = {a: 3};
+  expect(fullIntersection([],[])).toEqual(true);
+  expect(fullIntersection([1],[1])).toEqual(true);
+  expect(fullIntersection([1, 2, 3], [1, 2])).toEqual(true);
+  expect(fullIntersection([1, [2, 3], a], [a, 1, [2, 3]])).toEqual(false);
+  expect(fullIntersection([null, 1, 2, 3, null, [6]], [4, 5])).toEqual(false);
+});