Make `Blob.prototype.type` more spec compliant

3 files changed, 41 insertions, 8 deletions

diff --git a/src/bun.js/bindings/bindings.zig b/src/bun.js/bindings/bindings.zig
index d21250567..4df5e1996 100644
--- a/src/bun.js/bindings/bindings.zig
+++ b/src/bun.js/bindings/bindings.zig
@@ -2276,6 +2276,10 @@ pub const JSGlobalObject = extern struct {
         return this.bunVM().allocator;
     }
 
+    pub fn throwOutOfMemory(this: *JSGlobalObject) void {
+        this.throwValue(this.createErrorInstance("Out of memory", .{}));
+    }
+
     pub fn throwInvalidArguments(
         this: *JSGlobalObject,
         comptime fmt: string,
diff --git a/src/bun.js/webcore/blob.zig b/src/bun.js/webcore/blob.zig
index c95aad48e..a593bfe05 100644
--- a/src/bun.js/webcore/blob.zig
+++ b/src/bun.js/webcore/blob.zig
@@ -2507,19 +2507,31 @@ pub const Blob = struct {
         globalThis: *JSC.JSGlobalObject,
         value: JSC.JSValue,
     ) callconv(.C) bool {
-        var zig_str = value.getZigString(globalThis);
-        if (zig_str.is16Bit())
-            return false;
+        const zig_str = if (value.isString())
+            value.getZigString(globalThis)
+        else
+            ZigString.Empty;
 
-        var slice = zig_str.trimmedSlice();
-        if (strings.eql(slice, this.content_type))
+        if (zig_str.eql(ZigString.init(this.content_type))) {
             return true;
+        }
 
         const prev_content_type = this.content_type;
         {
-            defer if (this.content_type_allocated) bun.default_allocator.free(prev_content_type);
-            var content_type_buf = globalThis.allocator().alloc(u8, slice.len) catch unreachable;
-            this.content_type = strings.copyLowercase(slice, content_type_buf);
+            var slicer = zig_str.toSlice(bun.default_allocator);
+            defer slicer.deinit();
+            const allocated = this.content_type_allocated;
+            defer if (allocated) bun.default_allocator.free(prev_content_type);
+            if (globalThis.bunVM().mimeType(slicer.slice())) |mime| {
+                this.content_type = mime.value;
+                this.content_type_allocated = false;
+                return true;
+            }
+            var content_type_buf = globalThis.allocator().alloc(u8, slicer.len) catch {
+                globalThis.throwOutOfMemory();
+                return false;
+            };
+            this.content_type = strings.copyLowercase(slicer.slice(), content_type_buf);
         }
 
         this.content_type_allocated = true;
diff --git a/test/js/web/fetch/blob.test.ts b/test/js/web/fetch/blob.test.ts
index ba44f8c1b..51b9c0ea8 100644
--- a/test/js/web/fetch/blob.test.ts
+++ b/test/js/web/fetch/blob.test.ts
@@ -28,6 +28,23 @@ test("Blob.slice", () => {
   expect(blob.slice("text/plain;charset=utf-8").type).toBe("text/plain;charset=utf-8");
 });
 
+test("Blob.prototype.type setter", () => {
+  var blob = new Blob(["Bun", "Foo"], { type: "text/foo" });
+  expect(blob.type).toBe("text/foo");
+  blob.type = "text/bar";
+  expect(blob.type).toBe("text/bar");
+  blob.type = "text/baz";
+  expect(blob.type).toBe("text/baz");
+  blob.type = "text/baz; charset=utf-8";
+  expect(blob.type).toBe("text/baz; charset=utf-8");
+  // @ts-expect-error
+  blob.type = NaN;
+  expect(blob.type).toBe("");
+  // @ts-expect-error
+  blob.type = Symbol();
+  expect(blob.type).toBe("");
+});
+
 test("new Blob", () => {
   var blob = new Blob(["Bun", "Foo"], { type: "text/foo" });
   expect(blob.size).toBe(6);