From 4577c2c6ac3033e6e901a03acdc9fc313ebd95fb Mon Sep 17 00:00:00 2001
From: = <=>
Date: Wed, 15 May 2024 19:21:51 +0300
Subject: [PATCH] feature: add-map-array-to-key-value-map-function

---
 ...ap-array-to-key-value-map.function.spec.ts | 33 +++++++++++++++++++
 .../map-array-to-key-value-map.function.ts    |  3 ++
 2 files changed, 36 insertions(+)
 create mode 100644 packages/common/src/map-array-to-key-value-map.function.spec.ts
 create mode 100644 packages/common/src/map-array-to-key-value-map.function.ts

diff --git a/packages/common/src/map-array-to-key-value-map.function.spec.ts b/packages/common/src/map-array-to-key-value-map.function.spec.ts
new file mode 100644
index 0000000..1eed929
--- /dev/null
+++ b/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' });
+  });
+});
diff --git a/packages/common/src/map-array-to-key-value-map.function.ts b/packages/common/src/map-array-to-key-value-map.function.ts
new file mode 100644
index 0000000..e97b40b
--- /dev/null
+++ b/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]));
+}