diff --git a/feature_tests/js/api/MyStruct.mjs b/feature_tests/js/api/MyStruct.mjs
index c28658d61..02a17b9b3 100644
--- a/feature_tests/js/api/MyStruct.mjs
+++ b/feature_tests/js/api/MyStruct.mjs
@@ -134,7 +134,7 @@ export class MyStruct {
         try {
             if (!diplomatReceive.resultFlag) {
                 const cause = new MyZst();
-                throw new Error('MyZst', { cause });
+                throw new globalThis.Error('MyZst', { cause });
             }
     
         }
diff --git a/feature_tests/js/api/ResultOpaque.mjs b/feature_tests/js/api/ResultOpaque.mjs
index 6f50055f5..4ec1b1ae3 100644
--- a/feature_tests/js/api/ResultOpaque.mjs
+++ b/feature_tests/js/api/ResultOpaque.mjs
@@ -36,7 +36,7 @@ export class ResultOpaque {
         try {
             if (!diplomatReceive.resultFlag) {
                 const cause = ErrorEnum[Array.from(ErrorEnum.values.keys())[diplomatRuntime.enumDiscriminant(wasm, diplomatReceive.buffer)]];
-                throw new Error('ErrorEnum: ' + cause.value, { cause });
+                throw new globalThis.Error('ErrorEnum: ' + cause.value, { cause });
             }
             return new ResultOpaque(diplomatRuntime.ptrRead(wasm, diplomatReceive.buffer), []);
         }
@@ -54,7 +54,7 @@ export class ResultOpaque {
         try {
             if (!diplomatReceive.resultFlag) {
                 const cause = ErrorEnum[Array.from(ErrorEnum.values.keys())[diplomatRuntime.enumDiscriminant(wasm, diplomatReceive.buffer)]];
-                throw new Error('ErrorEnum: ' + cause.value, { cause });
+                throw new globalThis.Error('ErrorEnum: ' + cause.value, { cause });
             }
             return new ResultOpaque(diplomatRuntime.ptrRead(wasm, diplomatReceive.buffer), []);
         }
@@ -72,7 +72,7 @@ export class ResultOpaque {
         try {
             if (!diplomatReceive.resultFlag) {
                 const cause = ErrorEnum[Array.from(ErrorEnum.values.keys())[diplomatRuntime.enumDiscriminant(wasm, diplomatReceive.buffer)]];
-                throw new Error('ErrorEnum: ' + cause.value, { cause });
+                throw new globalThis.Error('ErrorEnum: ' + cause.value, { cause });
             }
             return new ResultOpaque(diplomatRuntime.ptrRead(wasm, diplomatReceive.buffer), []);
         }
@@ -107,7 +107,7 @@ export class ResultOpaque {
         try {
             if (!diplomatReceive.resultFlag) {
                 const cause = new ErrorStruct()._fromFFI(diplomatReceive.buffer);
-                throw new Error('ErrorStruct: ' + cause.toString(), { cause });
+                throw new globalThis.Error('ErrorStruct: ' + cause.toString(), { cause });
             }
             return new ResultOpaque(diplomatRuntime.ptrRead(wasm, diplomatReceive.buffer), []);
         }
@@ -125,7 +125,7 @@ export class ResultOpaque {
         try {
             if (!diplomatReceive.resultFlag) {
                 const cause = new ResultOpaque(diplomatRuntime.ptrRead(wasm, diplomatReceive.buffer), []);
-                throw new Error('ResultOpaque: ' + cause.toString(), { cause });
+                throw new globalThis.Error('ResultOpaque: ' + cause.toString(), { cause });
             }
     
         }
@@ -160,7 +160,7 @@ export class ResultOpaque {
         try {
             if (!diplomatReceive.resultFlag) {
                 const cause = new ResultOpaque(diplomatRuntime.ptrRead(wasm, diplomatReceive.buffer), []);
-                throw new Error('ResultOpaque: ' + cause.toString(), { cause });
+                throw new globalThis.Error('ResultOpaque: ' + cause.toString(), { cause });
             }
             return ErrorEnum[Array.from(ErrorEnum.values.keys())[diplomatRuntime.enumDiscriminant(wasm, diplomatReceive.buffer)]];
         }
diff --git a/tool/src/js/formatter.rs b/tool/src/js/formatter.rs
index fe7bc0d7d..d6a4f58b8 100644
--- a/tool/src/js/formatter.rs
+++ b/tool/src/js/formatter.rs
@@ -37,12 +37,16 @@ const RESERVED: &[&str] = &[
     "true",
     "try",
     "typeof",
+    "undefined",
     "var",
     "void",
     "while",
     "with",
 ];
 
+/// From https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects
+const RESERVED_TYPES: &[&str] = &["Infinity", "NaN"];
+
 /// Helper class for us to format JS identifiers from the HIR.
 pub(crate) struct JSFormatter<'tcx> {
     /// Per [`CFormatter`]'s documentation we use it for support.
@@ -60,10 +64,16 @@ impl<'tcx> JSFormatter<'tcx> {
     pub fn fmt_type_name(&self, id: TypeId) -> Cow<'tcx, str> {
         let type_def = self.tcx.resolve_type(id);
 
-        type_def
+        let name = type_def
             .attrs()
             .rename
-            .apply(type_def.name().as_str().into())
+            .apply(type_def.name().as_str().into());
+
+        if RESERVED_TYPES.contains(&&*name) || RESERVED.contains(&&*name) {
+            panic!("{name} is not an allowed type in JS. Please rename.")
+        }
+
+        name
     }
 
     pub fn fmt_file_name_extensionless(&self, type_name: &str) -> String {
diff --git a/tool/src/js/type_generation/converter.rs b/tool/src/js/type_generation/converter.rs
index bd51d77bf..88c9c139c 100644
--- a/tool/src/js/type_generation/converter.rs
+++ b/tool/src/js/type_generation/converter.rs
@@ -438,7 +438,7 @@ impl<'jsctx, 'tcx> TyGenContext<'jsctx, 'tcx> {
                             let cause =
                                 self.gen_c_to_js_for_type(e, receive_deref, &method.lifetime_env);
                             format!(
-                            "const cause = {cause};\n    throw new Error({message}, {{ cause }})", 
+                            "const cause = {cause};\n    throw new globalThis.Error({message}, {{ cause }})", 
                             message = match e {
                                 Type::Enum(..) => format!("'{type_name}: ' + cause.value"),
                                 Type::Struct(s) if match s.resolve(self.tcx) {