feat: Added a new utility function typeUtil & fix: Fix bug in clearNullProperties utility function

README.md

@@ -32,6 +32,7 @@ import {
   commonUtil,
   formatUtil,
   searchQueryUtil,
+  typeUtil,
   deviceUtil,
 } from "kr-corekit";
 
@@ -73,6 +74,10 @@ const copied = await commonUtil.copyToClipboard("Hello, World!"); // true if suc
 // Search Query utilities
 const queryParams = searchQueryUtil.getAllQuery(); // { key: ["value1", "value2"], id: "123" }
 
+// Type utilities
+const isPlain = typeUtil.isPlainObject({}); // true
+const isNotPlain = typeUtil.isPlainObject(new Date()); // false
+
 // Device utilities
 const device = deviceUtil.getDevice(); // { isMobile: false, isTablet: false, isDesktop: true, isIOS: false, isAndroid: false }
 
@@ -125,6 +130,10 @@ const formattedPhone = formatUtil.formatPhoneNumber("01012345678"); // "010-1234
 
 - `getAllQuery(): Record<string, string | string[]>` - Parses the current URL's query string and returns an object with key-value pairs. Values appear as arrays when the same key is used multiple times.
 
+### TypeUtil
+
+- `isPlainObject(value: unknown): boolean` - Checks if a value is a plain object (created by Object literal or Object.create(null)), excluding arrays, dates, and other built-in objects.
+
 ### DeviceUtil
 
 - `getDevice(): DeviceInfo` - Detects the user's device environment. Returns information about device type (mobile/tablet/desktop) and operating system (iOS/Android). Uses navigator.userAgent for detection and provides safe fallback for SSR environments.

package/index.ts

@@ -1,7 +1,19 @@
+// 네임스페이스에 대한 익스포트 진행
 export * as stringUtil from "./stringUtil";
 export * as objectUtil from "./objectUtil";
 export * as cookieUtil from "./cookieUtil";
 export * as numberUtil from "./numberUtil";
 export * as validationUtil from "./validationUtil";
 export * as commonUtil from "./commonUtil";
 export * as searchQueryUtil from "./searchQueryUtil";
+export * as typeUtil from "./typeUtil";
+
+// 개별 함수에 대한 익스포트 진행
+export * from "./stringUtil";
+export * from "./objectUtil";
+export * from "./cookieUtil";
+export * from "./numberUtil";
+export * from "./validationUtil";
+export * from "./commonUtil";
+export * from "./searchQueryUtil";
+export * from "./typeUtil";

package/objectUtil/clearNullProperties/index.test.ts

@@ -6,3 +6,27 @@ test("만약 Null이 객체에 존재한다면, Null이 없는 객체가 반환
   const result = clearNullProperties(obj);
   expect(result).toEqual({ a: 1, b: 2 });
 });
+
+test("만약 배열이 포함된 객체가 존재한다면, 그대로 반환된다.", () => {
+  const obj = { a: 1, b: [1, 2, 3], c: null };
+  const result = clearNullProperties(obj);
+  expect(result).toEqual({ a: 1, b: [1, 2, 3] });
+});
+
+test("만약 중첩된 객체가 존재한다면, 중첩된 객체의 Null도 제거된다.", () => {
+  const obj = { a: 1, b: { c: null, d: 4 }, e: null };
+  const result = clearNullProperties(obj);
+  expect(result).toEqual({ a: 1, b: { d: 4 } });
+});
+
+test("만약 모든 속성이 Null이라면, 빈 객체가 반환된다.", () => {
+  const obj = { a: null, b: null };
+  const result = clearNullProperties(obj);
+  expect(result).toEqual({});
+});
+
+test("만약 속성에 false 값이 존재한다면, false 값은 유지된다.", () => {
+  const obj = { a: false, b: null };
+  const result = clearNullProperties(obj);
+  expect(result).toEqual({ a: false });
+});

package/objectUtil/clearNullProperties/index.ts

@@ -1,11 +1,18 @@
+import isPlainObject from "../../typeUtil/isPlainObject";
+
 export default function clearNullProperties<T>(obj: T): T {
-    const result = { ...obj };
-    Object.keys(result as Record<string, any>).forEach((el) => {
-        if (!(result as Record<string, any>)[el]) {
-            delete (result as Record<string, any>)[el];
-        } else if (typeof (result as Record<string, any>)[el] === "object") {
-            (result as Record<string, any>)[el] = clearNullProperties((result as Record<string, any>)[el]);
-        }
-    })
-    return result;
+  const result = { ...obj };
+  Object.keys(result as Record<string, any>).forEach((el) => {
+    if (
+      (result as Record<string, any>)[el] === null ||
+      (result as Record<string, any>)[el] === undefined
+    ) {
+      delete (result as Record<string, any>)[el];
+    } else if (isPlainObject((result as Record<string, any>)[el])) {
+      (result as Record<string, any>)[el] = clearNullProperties(
+        (result as Record<string, any>)[el]
+      );
+    }
+  });
+  return result;
 }

package/typeUtil/index.ts

@@ -0,0 +1 @@
+export { default as isPlainObject } from "./isPlainObject";

package/typeUtil/isPlainObject/index.test.ts

@@ -0,0 +1,28 @@
+import { describe, expect, test } from "vitest";
+import isPlainObject from ".";
+
+describe("isPlainObject 유틸 함수 테스트", () => {
+  test("일반 객체는 true를 반환한다", () => {
+    const obj = { a: 1, b: 2 };
+    expect(isPlainObject(obj)).toBe(true);
+  });
+
+  test("배열은 false를 반환한다", () => {
+    const arr = [1, 2, 3];
+    expect(isPlainObject(arr)).toBe(false);
+  });
+
+  test("null은 false를 반환한다", () => {
+    expect(isPlainObject(null)).toBe(false);
+  });
+
+  test("날짜 객체는 false를 반환한다", () => {
+    const date = new Date();
+    expect(isPlainObject(date)).toBe(false);
+  });
+
+  test("커스텀 프로토타입을 가진 객체는 false를 반환한다", () => {
+    const obj = Object.create({ a: 1 });
+    expect(isPlainObject(obj)).toBe(false);
+  });
+});

package/typeUtil/isPlainObject/index.ts

@@ -0,0 +1,10 @@
+export default function isPlainObject(value: unknown): boolean {
+  if (typeof value !== "object" || value === null) {
+    return false;
+  }
+
+  return (
+    Object.getPrototypeOf(value) === Object.prototype ||
+    Object.getPrototypeOf(value) === null
+  );
+}