Add MimeType utility functions

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+
+- `isImageMimeType`, `isPdfMimeType`, `isVideoMimeType`, `isAudioMimeType`, `isTextMimeType`, and `isApplicationMimeType` MIME type utility functions
+
 ## [1.4.0] - 2025-06-24
 
 ### Added

src/index.ts

@@ -4,6 +4,7 @@ export * from "./lib/date";
 export * from "./lib/enum";
 export * from "./lib/guid";
 export * from "./lib/localStorage";
+export * from "./lib/mimeType";
 export * from "./lib/number";
 export * from "./lib/object";
 export * from "./lib/string";

src/lib/mimeType.spec.ts

@@ -0,0 +1,122 @@
+import { isImageMimeType, isPdfMimeType, isVideoMimeType, isAudioMimeType, isTextMimeType, isApplicationMimeType } from "./mimeType";
+
+describe("mimeType tests", () => {
+  // Common invalid inputs
+  const invalidInputs: [string | null | undefined | number | Date, boolean][] = [
+    [null as unknown as string, false],
+    [undefined as unknown as string, false],
+    [0 as unknown as string, false],
+    [new Date() as unknown as string, false],
+    ["", false],
+    [" ", false],
+    ["not-a-mime-type", false],
+  ];
+
+  test.each([
+    ...invalidInputs,
+    // Valid image MIME types
+    ["image/jpeg", true],
+    ["image/png", true],
+    ["image/gif", true],
+    ["image/webp", true],
+    ["image/svg+xml", true],
+    ["IMAGE/JPEG", true], // Case insensitive
+    ["  image/gif  ", true], // Whitespace trimmed
+    // Invalid cases
+    ["application/pdf", false],
+    ["text/plain", false],
+    ["video/mp4", false],
+    ["image", false],
+    ["image/", false],
+    ["/image", false],
+  ])("isImageMimeType", (mimeType, expected) => {
+    expect(isImageMimeType(mimeType as string)).toBe(expected);
+  });
+
+  test.each([
+    ...invalidInputs,
+    // Valid PDF MIME type
+    ["application/pdf", true],
+    ["APPLICATION/PDF", true], // Case insensitive
+    ["  application/pdf  ", true], // Whitespace trimmed
+    // Invalid cases
+    ["image/jpeg", false],
+    ["application/json", false],
+    ["pdf", false],
+    ["application/", false],
+  ])("isPdfMimeType", (mimeType, expected) => {
+    expect(isPdfMimeType(mimeType as string)).toBe(expected);
+  });
+
+  test.each([
+    ...invalidInputs,
+    // Valid video MIME types
+    ["video/mp4", true],
+    ["video/mpeg", true],
+    ["video/webm", true],
+    ["VIDEO/MP4", true], // Case insensitive
+    ["  video/webm  ", true], // Whitespace trimmed
+    // Invalid cases
+    ["image/jpeg", false],
+    ["audio/mp3", false],
+    ["video", false],
+    ["video/", false],
+    ["/video", false],
+  ])("isVideoMimeType", (mimeType, expected) => {
+    expect(isVideoMimeType(mimeType as string)).toBe(expected);
+  });
+
+  test.each([
+    ...invalidInputs,
+    // Valid audio MIME types
+    ["audio/mp3", true],
+    ["audio/mpeg", true],
+    ["audio/wav", true],
+    ["AUDIO/MP3", true], // Case insensitive
+    ["  audio/ogg  ", true], // Whitespace trimmed
+    // Invalid cases
+    ["video/mp4", false],
+    ["image/jpeg", false],
+    ["audio", false],
+    ["audio/", false],
+    ["/audio", false],
+  ])("isAudioMimeType", (mimeType, expected) => {
+    expect(isAudioMimeType(mimeType as string)).toBe(expected);
+  });
+
+  test.each([
+    ...invalidInputs,
+    // Valid text MIME types
+    ["text/plain", true],
+    ["text/html", true],
+    ["text/css", true],
+    ["TEXT/PLAIN", true], // Case insensitive
+    ["  text/css  ", true], // Whitespace trimmed
+    // Invalid cases
+    ["application/pdf", false],
+    ["image/jpeg", false],
+    ["text", false],
+    ["text/", false],
+    ["/text", false],
+  ])("isTextMimeType", (mimeType, expected) => {
+    expect(isTextMimeType(mimeType as string)).toBe(expected);
+  });
+
+  test.each([
+    ...invalidInputs,
+    // Valid application MIME types
+    ["application/pdf", true],
+    ["application/json", true],
+    ["application/xml", true],
+    ["APPLICATION/PDF", true], // Case insensitive
+    ["  application/xml  ", true], // Whitespace trimmed
+    // Invalid cases
+    ["text/plain", false],
+    ["image/jpeg", false],
+    ["application", false],
+    ["application/", false],
+    ["/application", false],
+  ])("isApplicationMimeType", (mimeType, expected) => {
+    expect(isApplicationMimeType(mimeType as string)).toBe(expected);
+  });
+});

src/lib/mimeType.ts

@@ -0,0 +1,91 @@
+import { isNullOrEmpty } from "./string";
+
+/**
+ * Private helper function to check if a MIME type matches a main type pattern
+ * @param mimeType The MIME type to check
+ * @param mainType The main MIME type (e.g., "image", "video")
+ * @returns true if the MIME type matches the pattern
+ */
+function isMainMimeType(mimeType: string, mainType: string): boolean {
+  const normalizedMimeType = mimeType.toLowerCase().trim();
+  return normalizedMimeType.startsWith(`${mainType}/`) && normalizedMimeType.length > mainType.length + 1;
+}
+
+/**
+ * Check if the MIME type represents an image
+ * @param mimeType The MIME type to check
+ * @returns true if the MIME type is for an image
+ */
+export function isImageMimeType(mimeType?: string): boolean {
+  if (isNullOrEmpty(mimeType)) {
+    return false;
+  }
+
+  return isMainMimeType(mimeType!, "image");
+}
+
+/**
+ * Check if the MIME type represents a PDF document
+ * @param mimeType The MIME type to check
+ * @returns true if the MIME type is for a PDF document
+ */
+export function isPdfMimeType(mimeType?: string): boolean {
+  if (isNullOrEmpty(mimeType)) {
+    return false;
+  }
+
+  const normalizedMimeType = mimeType!.toLowerCase().trim();
+  return normalizedMimeType === "application/pdf";
+}
+
+/**
+ * Check if the MIME type represents a video
+ * @param mimeType The MIME type to check
+ * @returns true if the MIME type is for a video
+ */
+export function isVideoMimeType(mimeType?: string): boolean {
+  if (isNullOrEmpty(mimeType)) {
+    return false;
+  }
+
+  return isMainMimeType(mimeType!, "video");
+}
+
+/**
+ * Check if the MIME type represents an audio file
+ * @param mimeType The MIME type to check
+ * @returns true if the MIME type is for an audio file
+ */
+export function isAudioMimeType(mimeType?: string): boolean {
+  if (isNullOrEmpty(mimeType)) {
+    return false;
+  }
+
+  return isMainMimeType(mimeType!, "audio");
+}
+
+/**
+ * Check if the MIME type represents a text file
+ * @param mimeType The MIME type to check
+ * @returns true if the MIME type is for a text file
+ */
+export function isTextMimeType(mimeType?: string): boolean {
+  if (isNullOrEmpty(mimeType)) {
+    return false;
+  }
+
+  return isMainMimeType(mimeType!, "text");
+}
+
+/**
+ * Check if the MIME type represents an application file
+ * @param mimeType The MIME type to check
+ * @returns true if the MIME type is for an application file
+ */
+export function isApplicationMimeType(mimeType?: string): boolean {
+  if (isNullOrEmpty(mimeType)) {
+    return false;
+  }
+
+  return isMainMimeType(mimeType!, "application");
+}