feat: add arrayMove function

src/functions/array-move.spec.ts

@@ -0,0 +1,26 @@
+import {arrayMove} from '../index'
+
+describe('Array Move', () => {
+  it('should move objects in an array', () => {
+    const a = [1, 2, 3, 4, 5, 6]
+
+    const b = arrayMove(a, 1, 2)
+    expect(b).toStrictEqual([1, 3, 2, 4, 5, 6])
+    expect(a).toStrictEqual([1, 2, 3, 4, 5, 6]) // We don't want to effect the original array
+
+    const c = arrayMove(a, 1, 10)
+    expect(c).toStrictEqual([
+      1,
+      3,
+      4,
+      5,
+      6,
+      undefined,
+      undefined,
+      undefined,
+      undefined,
+      undefined,
+      2
+    ])
+  })
+})

src/functions/array-move.ts

@@ -0,0 +1,25 @@
+/**
+ * Move an index to another within the given array.
+ *
+ * @param originalArray The array to move objects in.
+ * @param oldIndex The index to move.
+ * @param newIndex The index to move the entry to.
+ * @returns The array with the elements moved.
+ */
+export const arrayMove = <T>(
+  originalArray: T[],
+  oldIndex: number,
+  newIndex: number
+): T[] => {
+  const array: (T | undefined)[] = [...originalArray]
+
+  if (newIndex >= array.length) {
+    let key = newIndex - array.length + 1
+    while (key--) {
+      array.push(undefined)
+    }
+  }
+  array.splice(newIndex, 0, array.splice(oldIndex, 1)[0])
+
+  return array as T[]
+}

src/index.ts

@@ -1,6 +1,7 @@
 export {BitMask} from './classes/bit-mask'
 export {Logger} from './classes/logger'
 
+export {arrayMove} from './functions/array-move'
 export {asyncForEach} from './functions/async-for-each'
 export {asyncMap} from './functions/async-map'
 export {