feature: add-map-array-to-key-value-map-function

packages/common/src/map-array-to-key-value-map.function.spec.ts

@@ -0,0 +1,33 @@
+import { mapArrayToKeyValueMap } from './map-array-to-key-value-map.function';
+
+describe('mapArrayToKeyValueMap function', () => {
+  it('should return an empty Map if the input array is empty', () => {
+    const result: Map<never, never> = mapArrayToKeyValueMap([], 'key');
+    expect(result.size).toBe(0);
+  });
+
+  it('should correctly map the array elements to key-value pairs in the Map', () => {
+    const array: { id: number; name: string }[] = [
+      { id: 1, name: 'Alice' },
+      { id: 2, name: 'Bob' },
+      { id: 3, name: 'Charlie' }
+    ];
+    const result: Map<number, { id: number; name: string }> = mapArrayToKeyValueMap(array, 'id');
+    expect(result.size).toBe(3);
+    expect(result.get(1)).toEqual({ id: 1, name: 'Alice' });
+    expect(result.get(2)).toEqual({ id: 2, name: 'Bob' });
+    expect(result.get(3)).toEqual({ id: 3, name: 'Charlie' });
+  });
+
+  it('should handle arrays with duplicate keys correctly', () => {
+    const array: { id: number; name: string }[] = [
+      { id: 1, name: 'Alice' },
+      { id: 2, name: 'Bob' },
+      { id: 1, name: 'Charlie' }
+    ];
+    const result: Map<number, { id: number; name: string }> = mapArrayToKeyValueMap(array, 'id');
+    expect(result.size).toBe(2);
+    expect(result.get(1)).toEqual({ id: 1, name: 'Charlie' });
+    expect(result.get(2)).toEqual({ id: 2, name: 'Bob' });
+  });
+});

packages/common/src/map-array-to-key-value-map.function.ts

@@ -0,0 +1,3 @@
+export function mapArrayToKeyValueMap<T extends object, Key extends keyof T>(array: T[], key: Key): Map<T[Key], T> {
+  return new Map<T[Key], T>(array.map((item: T) => [item[key], item]));
+}