feat: Add checkBase64 util function

README.md

@@ -48,6 +48,7 @@ const difference = numberUtil.subtract(10, 3); // 7
 const isValid = validationUtil.checkEmail("user@example.com"); // true
 const isHttpUrl = validationUtil.checkHttpUrl("https://example.com"); // true
 const isDomain = validationUtil.checkDomain("example.com"); // true
+const isBase64 = validationUtil.checkBase64("U29tZSB2YWxpZCBiYXNlNjQgc3RyaW5n"); // true
 
 // Common utilities
 const empty = commonUtil.isEmpty(""); // true
@@ -83,6 +84,7 @@ const theme = cookieUtil.getCookie("theme");
 - `checkEmail(email: string): boolean` - Validates email format
 - `checkHttpUrl(url: string): boolean` - Validates HTTP/HTTPS URL format
 - `checkDomain(domain: string): boolean` - Validates domain name format
+- `checkBase64(value: string): boolean` - Validates whether a string is a valid base64 encoded value
 
 ### CommonUtil
 

package/validationUtil/checkBase64/index.test.ts

@@ -0,0 +1,19 @@
+import { describe, expect, it } from "vitest";
+import checkBase64 from ".";
+
+describe("checkBase64 유틸 함수 테스트", () => {
+  it("유효한 base64 문자열에 대해 true를 반환해야 합니다.", () => {
+    expect(checkBase64("U29tZSB2YWxpZCBiYXNlNjQgc3RyaW5n")).toBe(true);
+    expect(checkBase64("SGVsbG8gd29ybGQ=")).toBe(true);
+  });
+
+  it("유효하지 않은 base64 문자열에 대해 false를 반환해야 합니다.", () => {
+    expect(checkBase64("bfdbfdbsba")).toBe(false);
+    expect(checkBase64("U29tZSB2YWxpZCBiYXNlNjQgc3RyaW5n===")).toBe(false);
+  });
+
+  it("만약 빈 문자열로 함수를 호출할 경우 false를 반환해야 합니다.", () => {
+    expect(checkBase64("")).toBe(false);
+    expect(checkBase64(" ")).toBe(false);
+  });
+});

package/validationUtil/checkBase64/index.ts

@@ -0,0 +1,6 @@
+export default function checkBase64(value: string): boolean {
+  if (value.trim() === "") return false;
+  const base64Regex =
+    /^(?:[A-Z0-9+\/]{4})*(?:[A-Z0-9+\/]{2}==|[A-Z0-9+\/]{3}=)?$/i;
+  return base64Regex.test(value);
+}

package/validationUtil/index.ts

@@ -1,3 +1,4 @@
 export { default as checkEmail } from "./checkEmail";
 export { default as checkHttpUrl } from "./checkHttpUrl";
 export { default as checkDomain } from "./checkDomain";
+export { default as checkBase64 } from "./checkBase64";