Set charset=utf-8 for better consistentcy

integration/bunjs-only-snippets/fetch.test.js

@@ -280,13 +280,17 @@ describe("Response", () => {
     it("sets the content-type header", () => {
       let response = Response.json("hello");
       expect(response.type).toBe("basic");
-      expect(response.headers.get("content-type")).toBe("application/json");
+      expect(response.headers.get("content-type")).toBe(
+        "application/json;charset=utf-8"
+      );
       expect(response.status).toBe(200);
     });
     it("supports number status code", () => {
       let response = Response.json("hello", 407);
       expect(response.type).toBe("basic");
-      expect(response.headers.get("content-type")).toBe("application/json");
+      expect(response.headers.get("content-type")).toBe(
+        "application/json;charset=utf-8"
+      );
       expect(response.status).toBe(407);
     });
     it("overrides the content-type header", () => {
@@ -296,7 +300,9 @@ describe("Response", () => {
         },
       });
       expect(response.type).toBe("basic");
-      expect(response.headers.get("content-type")).toBe("application/json");
+      expect(response.headers.get("content-type")).toBe(
+        "application/json;charset=utf-8"
+      );
     });
     it("supports headers", () => {
       var response = Response.json("hello", {
@@ -306,7 +312,9 @@ describe("Response", () => {
         },
         statusCode: 408,
       });
-      expect(response.headers.get("content-type")).toBe("application/json");
+      expect(response.headers.get("content-type")).toBe(
+        "application/json;charset=utf-8"
+      );
       expect(response.headers.get("x-hello")).toBe("world");
       expect(response.status).toBe(408);
     });

src/http/mime_type.zig

@@ -63,7 +63,7 @@ pub const javascript = MimeType.initComptime("text/javascript;charset=utf-8", .j
 pub const ico = MimeType.initComptime("image/vnd.microsoft.icon", .image);
 pub const html = MimeType.initComptime("text/html;charset=utf-8", .html);
 // we transpile json to javascript so that it is importable without import assertions.
-pub const json = MimeType.initComptime("application/json", .json);
+pub const json = MimeType.initComptime("application/json;charset=utf-8", .json);
 pub const transpiled_json = javascript;
 pub const text = MimeType.initComptime("text/plain;charset=utf-8", .html);
 

src/javascript/jsc/webcore/response.zig

@@ -392,7 +392,7 @@ pub const Response = struct {
         }
 
         var headers_ref = response.getOrCreateHeaders().leak();
-        headers_ref.putHeaderNormalized("content-type", "application/json", false);
+        headers_ref.putHeaderNormalized("content-type", MimeType.json.value, false);
         var ptr = response.allocator.create(Response) catch unreachable;
         ptr.* = response;