diff --git a/src/browser/js/Local.zig b/src/browser/js/Local.zig
index af7d1116..8ef62701 100644
--- a/src/browser/js/Local.zig
+++ b/src/browser/js/Local.zig
@@ -1206,9 +1206,9 @@ pub fn stackTrace(self: *const Local) !?[]const u8 {
 }
 
 // == Promise Helpers ==
-pub fn rejectPromise(self: *const Local, comptime kind: js.PromiseResolver.RejectError) js.Promise {
+pub fn rejectPromise(self: *const Local, err: js.PromiseResolver.RejectError) js.Promise {
     var resolver = js.PromiseResolver.init(self);
-    resolver.rejectError("Local.rejectPromise", kind);
+    resolver.rejectError("Local.rejectPromise", err);
     return resolver.promise();
 }
 
diff --git a/src/browser/js/PromiseResolver.zig b/src/browser/js/PromiseResolver.zig
index 7743fa48..fb3192c0 100644
--- a/src/browser/js/PromiseResolver.zig
+++ b/src/browser/js/PromiseResolver.zig
@@ -20,7 +20,6 @@ const js = @import("js.zig");
 const v8 = js.v8;
 
 const log = @import("../../log.zig");
-const DOMException = @import("../webapi/DOMException.zig");
 
 const DOMException = @import("../webapi/DOMException.zig");
 
@@ -67,17 +66,13 @@ pub fn reject(self: PromiseResolver, comptime source: []const u8, value: anytype
     };
 }
 
-pub const RejectError = union(enum(u4)) {
+pub const RejectError = union(enum) {
     /// Not to be confused with `DOMException`; this is bare `Error`.
     generic_error: []const u8,
     range_error: []const u8,
     reference_error: []const u8,
     syntax_error: []const u8,
     type_error: []const u8,
-    wasm_compile_error: void, // TODO.
-    wasm_link_error: void, // TODO.
-    wasm_runtime_error: void, // TODO.
-    wasm_suspend_error: void, // TODO.
     /// DOM exceptions are unknown to V8, belongs to web standards.
     dom_exception: struct { err: anyerror },
 };
@@ -86,9 +81,9 @@ pub const RejectError = union(enum(u4)) {
 pub fn rejectError(
     self: PromiseResolver,
     comptime source: []const u8,
-    comptime kind: RejectError,
+    err: RejectError,
 ) void {
-    const handle = switch (kind) {
+    const handle = switch (err) {
         .generic_error => |msg| self.local.isolate.createError(msg),
         .range_error => |msg| self.local.isolate.createRangeError(msg),
         .reference_error => |msg| self.local.isolate.createReferenceError(msg),
@@ -101,7 +96,6 @@ pub fn rejectError(
             };
             return;
         },
-        inline else => unreachable,
     };
 
     self._reject(js.Value{ .handle = handle, .local = self.local }) catch |reject_err| {
diff --git a/src/browser/webapi/Navigator.zig b/src/browser/webapi/Navigator.zig
index 218110c9..49f1f716 100644
--- a/src/browser/webapi/Navigator.zig
+++ b/src/browser/webapi/Navigator.zig
@@ -73,7 +73,7 @@ pub fn getStorage(self: *Navigator) *StorageManager {
 
 pub fn getBattery(_: *const Navigator, page: *Page) !js.Promise {
     log.info(.not_implemented, "navigator.getBattery", .{});
-    return page.js.local.?.rejectErrorPromise(.{ .dom_exception = error.NotSupported });
+    return page.js.local.?.rejectErrorPromise(.{ .dom_exception = .{ .err = error.NotSupported } });
 }
 
 pub fn registerProtocolHandler(_: *const Navigator, scheme: []const u8, url: [:0]const u8, page: *const Page) !void {