fix(media-core): normalize GIF content type detection (#96435)

lin-hongkuan · vincentkoc · web-flow · commit 47d3d1b1f1b2 · 2026-06-25T01:09:10.000+08:00
Merged via squash. Prepared head SHA: 82b1396 Co-authored-by: lin-hongkuan <234943746+lin-hongkuan@users.noreply.github.com> Co-authored-by: vincentkoc <25068+vincentkoc@users.noreply.github.com> Reviewed-by: @vincentkoc
diff --git a/packages/media-core/src/mime.test.ts b/packages/media-core/src/mime.test.ts
@@ -8,6 +8,7 @@ import {
   FILE_TYPE_SNIFF_MAX_BYTES,
   imageMimeFromFormat,
   isAudioFileName,
+  isGifMedia,
   kindFromMime,
   mimeTypeFromFilePath,
   normalizeMimeType,
@@ -271,6 +272,29 @@ describe("isAudioFileName", () => {
   });
 });
 
+describe("isGifMedia", () => {
+  it.each([
+    {
+      opts: { contentType: "image/gif; charset=binary" },
+      expected: true,
+    },
+    {
+      opts: { contentType: " IMAGE/GIF " },
+      expected: true,
+    },
+    {
+      opts: { contentType: "image/png" },
+      expected: false,
+    },
+    {
+      opts: { fileName: "animation.GIF" },
+      expected: true,
+    },
+  ] as const)("detects GIF media from normalized metadata %#", ({ opts, expected }) => {
+    expect(isGifMedia(opts)).toBe(expected);
+  });
+});
+
 describe("normalizeMimeType", () => {
   function expectNormalizedMimeCase(
     input: Parameters<typeof normalizeMimeType>[0],
diff --git a/packages/media-core/src/mime.ts b/packages/media-core/src/mime.ts
@@ -252,7 +252,7 @@ export function isGifMedia(opts: {
   contentType?: string | null;
   fileName?: string | null;
 }): boolean {
-  if (opts.contentType?.toLowerCase() === "image/gif") {
+  if (normalizeMimeType(opts.contentType) === "image/gif") {
     return true;
   }
   const ext = getFileExtension(opts.fileName);

Original file line number	Diff line number	Diff line change
`@@ -252,7 +252,7 @@ export function isGifMedia(opts: {`
`252`	`252`	`contentType?: string \| null;`
`253`	`253`	`fileName?: string \| null;`
`254`	`254`	`}): boolean {`
`255`		`- if (opts.contentType?.toLowerCase() === "image/gif") {`
	`255`	`+ if (normalizeMimeType(opts.contentType) === "image/gif") {`
`256`	`256`	`return true;`
`257`	`257`	`}`
`258`	`258`	`const ext = getFileExtension(opts.fileName);`