feat(keyBy): Accept number and symbol keys in keyBy (toss#98)

src/array/keyBy.spec.ts

@@ -2,17 +2,39 @@ import { describe, expect, it } from 'vitest';
 import { keyBy } from './keyBy';
 
 describe('keyBy', () => {
-  it('should return the mapped object by given key', () => {
+  it('should map each element of an array by string key', () => {
     const people = [
       { name: 'mike', age: 20 },
       { name: 'jake', age: 30 },
     ];
 
-    const result = keyBy(people, person => person.age.toString());
+    const result = keyBy(people, person => person.name);
+    expect(result).toEqual({ mike: { name: 'mike', age: 20 }, jake: { name: 'jake', age: 30 } });
+  });
+
+  it('should map each element of an array by number key', () => {
+    const people = [
+      { name: 'mike', age: 20 },
+      { name: 'jake', age: 30 },
+    ];
+
+    const result = keyBy(people, person => person.age);
     expect(result).toEqual({ 20: { name: 'mike', age: 20 }, 30: { name: 'jake', age: 30 } });
+  });
+
+  it('should map each element of an array by symbol key', () => {
+    const id1 = Symbol('id');
+    const id2 = Symbol('id');
+    const people = [
+      { id: id1, name: 'mike', age: 20 },
+      { id: id2, name: 'jake', age: 30 },
+    ];
 
-    const result2 = keyBy(people, person => person.name);
-    expect(result2).toEqual({ mike: { name: 'mike', age: 20 }, jake: { name: 'jake', age: 30 } });
+    const result = keyBy(people, person => person.id);
+    expect(result).toEqual({
+      [id1]: { id: id1, name: 'mike', age: 20 },
+      [id2]: { id: id2, name: 'jake', age: 30 },
+    });
   });
 
   it('should overwrite the value when encountering the same key', () => {

src/array/keyBy.ts

@@ -23,7 +23,7 @@
  * //   vegetable: { category: 'vegetable', name: 'carrot' }
  * // }
  */
-export function keyBy<T, K extends string>(arr: readonly T[], getKeyFromItem: (item: T) => K): Record<K, T> {
+export function keyBy<T, K extends PropertyKey>(arr: readonly T[], getKeyFromItem: (item: T) => K): Record<K, T> {
   const result = {} as Record<K, T>;
 
   for (const item of arr) {