feat: intro isSubset

Author: s3xysteak

src/core/array.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest'
-import { groupBy } from '..'
+import { groupBy, isSubset } from '..'
 
 describe('groupBy', () => {
   it('should work with empty array', () => {
@@ -47,3 +47,33 @@ describe('groupBy', () => {
     expect(groupBy(arrMul, item => item.type)).toEqual(targetMul)
   })
 })
+
+describe('isSubset', () => {
+  it('array in array', () => {
+    expect(isSubset([1, 2], [1, 2, 3])).toBe(true)
+    expect(isSubset([1, 4], [1, 2, 3])).toBe(false)
+  })
+
+  it('set in array', () => {
+    expect(isSubset(new Set([1, 2]), [1, 2, 3])).toBe(true)
+  })
+
+  it('array in set', () => {
+    expect(isSubset([1, 2], new Set([1, 2, 3]))).toBe(true)
+  })
+
+  it('set in set', () => {
+    expect(isSubset(new Set([1, 2]), new Set([1, 2, 3]))).toBe(true)
+    expect(isSubset(new Set([1, 4]), new Set([1, 2, 3]))).toBe(false)
+  })
+
+  it('empty subset', () => {
+    expect(isSubset([], [1, 2, 3])).toBe(true)
+    expect(isSubset(new Set(), [1, 2, 3])).toBe(true)
+  })
+
+  it('subset same as superset', () => {
+    const arr = [1, 2, 3]
+    expect(isSubset(arr, arr)).toBe(true)
+  })
+})

src/core/array.ts

@@ -46,3 +46,21 @@ export function groupBy<T extends any[]>(arr: T, getKey: string | ((element: T[n
 
   return val
 }
+
+/**
+ * Is the first param a subset of the second
+ *
+ * @example
+ * isSubset([1, 2], [1, 2, 3]) // -> true
+ */
+export function isSubset<SubSet, SuperSet>(
+  subSet: Iterable<SubSet> | Set<SubSet>,
+  superSet: Iterable<SuperSet> | Set<SuperSet>,
+) {
+  const formatted = superSet instanceof Set ? superSet : new Set(superSet)
+  for (const item of subSet) {
+    if (!formatted.has(item as any))
+      return false
+  }
+  return true
+}