feat(findKey): add findKey to compat layer

benchmarks/performance/findKey.bench.ts

@@ -1,5 +1,6 @@
 import { bench, describe } from 'vitest';
 import { findKey as findKeyToolkit } from 'es-toolkit';
+import { findKey as findKeyCompatToolkit } from 'es-toolkit/compat';
 import { findKey as findKeyLodash } from 'lodash';
 
 describe('findKey', () => {
@@ -16,6 +17,10 @@ describe('findKey', () => {
   bench('lodash/findKey', () => {
     findKeyLodash(users, o => o.age < 40);
   });
+
+  bench('es-toolkit/compat/findKey', () => {
+    findKeyCompatToolkit(users, o => o.age < 40);
+  });
 });
 
 describe('findKey/largeObject', () => {
@@ -31,4 +36,8 @@ describe('findKey/largeObject', () => {
   bench('lodash/findKey', () => {
     findKeyLodash(largeUsers, o => o.age === 7000);
   });
+
+  bench('es-toolkit/compat/findKey', () => {
+    findKeyCompatToolkit(largeUsers, o => o.age === 7000);
+  });
 });

docs/ja/reference/object/findKey.md

@@ -2,7 +2,7 @@
 
 提供されたテスト関数を満たすオブジェクト内の最初の要素のキーを検索します。
 
-## Signature
+## インターフェース
 
 ```typescript
 function findKey<T extends Record<any, any>>(
@@ -11,16 +11,16 @@ function findKey<T extends Record<any, any>>(
 ): keyof T | undefined;
 ```
 
-### Parameters
+### パラメータ
 
 - `obj` (`T extends Record<any, any>`): 検索するオブジェクト。
 - `predicate` (`(value: T[keyof T], key: keyof T, obj: T) => boolean`): オブジェクト内の各値に対して実行する関数。
 
-### Returns
+### 戻り値
 
 (`keyof T | undefined`): 指定されたテスト関数を満たすオブジェクト内の最初の要素のキー。テストに合格する要素がない場合は未定義です。
 
-## Examples
+## 例
 
 ```typescript
 const users = {
@@ -32,3 +32,45 @@ const users = {
 findKey(users, o => o.age < 40); // 'pebbles'
 findKey(users, o => o.age > 50); // undefined
 ```
+
+## Lodash 互換性
+
+`es-toolkit/compat` から `findKey` をインポートすると、Lodash と互換になります。
+キーを検索する条件を、さまざまな方法で指定できます。
+
+- **検査関数**: 各要素に対して検査する関数を実行します。最初に `true` を返す要素のキーを返します。
+- **部分オブジェクト**: 指定されたオブジェクトと部分的に一致する要素のキーを返します。
+- **プロパティ-値ペア**: 指定されたプロパティと値が一致する要素のキーを返します。
+- **プロパティ名**: 指定されたプロパティに対して真と評価される要素のキーを返します。
+
+### インターフェース
+
+```typescript
+export function findKey<T extends Record<any, any>>(
+  obj: T,
+  conditionToFind: (value: T[keyof T], key: keyof T, obj: T) => boolean
+): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(obj: T, objectToFind: Partial<T[keyof T]>): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(
+  obj: T,
+  propertyToFind: [keyof T[keyof T], any]
+): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(obj: T, propertyToFind: keyof T[keyof T]): keyof T | undefined;
+```
+
+### 例
+
+```typescript
+const users = { barney: { age: 36 }, fred: { age: 40 } };
+
+findKey(users, o => o.age < 40);
+// => 'barney'
+findKey(users, { age: 36 });
+// => 'barney'
+findKey(users, ['age', 36]);
+// => 'barney'
+
+const languages = { javascript: { active: false }, typescript: { active: true } };
+findKey(users, 'active');
+// => 'typescript'
+```

docs/ko/reference/object/findKey.md

@@ -32,3 +32,46 @@ const users = {
 findKey(users, o => o.age < 40); // 'pebbles'
 findKey(users, o => o.age > 50); // undefined
 ```
+
+## Lodash와 호환성
+
+`es-toolkit/compat`에서 `findKey`를 가져오면 lodash와 완전히 호환돼요.
+
+키를 찾는 조건을 여러 방법으로 명시할 수 있어요.
+
+- **검사 함수**: 각각의 요소에 대해서 검사하는 함수를 실행해요. 처음으로 `true`를 반환하는 요소의 키를 반환해요.
+- **부분 객체**: 주어진 객체와 부분적으로 일치하는 요소의 키를 반환해요.
+- **프로퍼티-값 쌍**: 해당 프로퍼티와 값이 일치하는 요소의 키를 반환해요.
+- **프로퍼티 이름**: 해당 프로퍼티에 대해서 참으로 평가되는 요소의 키를 반환해요.
+
+### 인터페이스
+
+```typescript
+export function findKey<T extends Record<any, any>>(
+  obj: T,
+  conditionToFind: (value: T[keyof T], key: keyof T, obj: T) => boolean
+): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(obj: T, objectToFind: Partial<T[keyof T]>): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(
+  obj: T,
+  propertyToFind: [keyof T[keyof T], any]
+): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(obj: T, propertyToFind: keyof T[keyof T]): keyof T | undefined;
+```
+
+### 예시
+
+```typescript
+const users = { barney: { age: 36 }, fred: { age: 40 } };
+
+findKey(users, o => o.age < 40);
+// => 'barney'
+findKey(users, { age: 36 });
+// => 'barney'
+findKey(users, ['age', 36]);
+// => 'barney'
+
+const languages = { javascript: { active: false }, typescript: { active: true } };
+findKey(users, 'active');
+// => 'typescript'
+```

docs/reference/object/findKey.md

@@ -32,3 +32,46 @@ const users = {
 findKey(users, o => o.age < 40); // 'pebbles'
 findKey(users, o => o.age > 50); // undefined
 ```
+
+## Compatibility with Lodash
+
+Import `findKey` from `es-toolkit/compat` for full compatibility with lodash.
+
+You can specify the condition for finding keys in several ways:
+
+- **Predicate function**: You can provide a predicate function that will be applied to each value in the object. The function should return `true` for elements that match the criteria. The search continues until the predicate returns `true` for the first time.
+- **Partial object**: You can also provide a partial object, and the function will return the key of the first element in the object that matches the properties of the provided object.
+- **Property-value pair**: Alternatively, you can specify a property-value pair, where the function will return the key of the first element that has the specified property matching the given value.
+- **Property name**: Lastly, you can provide a property name, and the function will return the key of the first element where the specified property has a truthy value.
+
+### Signature
+
+```typescript
+export function findKey<T extends Record<any, any>>(
+  obj: T,
+  conditionToFind: (value: T[keyof T], key: keyof T, obj: T) => boolean
+): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(obj: T, objectToFind: Partial<T[keyof T]>): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(
+  obj: T,
+  propertyToFind: [keyof T[keyof T], any]
+): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(obj: T, propertyToFind: keyof T[keyof T]): keyof T | undefined;
+```
+
+### Examples
+
+```typescript
+const users = { barney: { age: 36 }, fred: { age: 40 } };
+
+findKey(users, o => o.age < 40);
+// => 'barney'
+findKey(users, { age: 36 });
+// => 'barney'
+findKey(users, ['age', 36]);
+// => 'barney'
+
+const languages = { javascript: { active: false }, typescript: { active: true } };
+findKey(users, 'active');
+// => 'typescript'
+```

docs/zh_hans/reference/object/findKey.md

@@ -32,3 +32,46 @@ const users = {
 findKey(users, o => o.age < 40); // 'pebbles'
 findKey(users, o => o.age > 50); // undefined
 ```
+
+## Lodash 兼容性
+
+从 `es-toolkit/compat` 导入 `findKey` 以实现与 lodash 的完全兼容。
+
+您可以通过多种方式指定查找键的条件。
+
+- **谓词函数**：对每个元素执行谓词函数。返回第一个返回 `true` 的元素的键。
+- **部分对象**：返回与给定对象部分匹配的元素的键。
+- **属性-值对**：返回具有指定属性和值匹配的元素的键。
+- **属性名**：返回指定属性评估为真的元素的键。
+
+### 签名
+
+```typescript
+export function findKey<T extends Record<any, any>>(
+  obj: T,
+  conditionToFind: (value: T[keyof T], key: keyof T, obj: T) => boolean
+): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(obj: T, objectToFind: Partial<T[keyof T]>): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(
+  obj: T,
+  propertyToFind: [keyof T[keyof T], any]
+): keyof T | undefined;
+export function findKey<T extends Record<any, any>>(obj: T, propertyToFind: keyof T[keyof T]): keyof T | undefined;
+```
+
+### 示例
+
+```typescript
+const users = { barney: { age: 36 }, fred: { age: 40 } };
+
+findKey(users, o => o.age < 40);
+// => 'barney'
+findKey(users, { age: 36 });
+// => 'barney'
+findKey(users, ['age', 36]);
+// => 'barney'
+
+const languages = { javascript: { active: false }, typescript: { active: true } };
+findKey(users, 'active');
+// => 'typescript'
+```

src/compat/index.ts

@@ -101,6 +101,7 @@ export { sumBy } from './math/sumBy.ts';
 
 export { cloneDeep } from './object/cloneDeep.ts';
 export { defaults } from './object/defaults.ts';
+export { findKey } from './object/findKey.ts';
 export { fromPairs } from './object/fromPairs.ts';
 export { get } from './object/get.ts';
 export { has } from './object/has.ts';

src/compat/object/findKey.spec.ts

@@ -0,0 +1,61 @@
+import { describe, expect, it } from 'vitest';
+import { findKey } from './findKey';
+
+/**
+ * @see https://lodash.com/docs/4.17.15#findKey
+ */
+describe('findKey', () => {
+  const users = {
+    barney: { age: 36, active: true },
+    fred: { age: 40, active: false },
+    pebbles: { age: 1, active: true },
+  };
+
+  it('should find key with a function predicate', function () {
+    const actual = findKey(users, function (o) {
+      return o.age < 40;
+    });
+    expect(actual).toBe('barney');
+  });
+
+  it('should work with `_.matches` shorthands', function () {
+    const actual = findKey(users, { age: 1, active: true });
+    expect(actual).toBe('pebbles');
+  });
+
+  it('should work with `_.matchesProperty` shorthands', function () {
+    const actual = findKey(users, ['active', false]);
+    expect(actual).toBe('fred');
+  });
+
+  it('should work with `_.property` shorthands', function () {
+    const actual = findKey(users, 'active');
+    expect(actual).toBe('barney');
+  });
+
+  it('should return undefined for an empty object', function () {
+    // @ts-expect-error - invalid argument
+    const actual = findKey({}, { age: 36 });
+    expect(actual).toBeUndefined();
+  });
+
+  it('should return undefined for null input', function () {
+    const actual = findKey(null, { age: 36 });
+    expect(actual).toBeUndefined();
+  });
+
+  it('should return undefined for undefined input', function () {
+    const actual = findKey(undefined, { age: 36 });
+    expect(actual).toBeUndefined();
+  });
+
+  it('should return undefined if no matching key is found', function () {
+    const actual = findKey(users, { age: 100 });
+    expect(actual).toBeUndefined();
+  });
+
+  it('should handle partial matches with `Partial<T[keyof T]>`', function () {
+    const actual = findKey(users, { active: true });
+    expect(actual).toBe('barney');
+  });
+});