diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index 9aaeda79f..b99909f20 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -16646,8 +16646,8 @@ interface WindowOrWorkerGlobalScope {
     readonly performance: Performance;
     atob(data: string): string;
     btoa(data: string): string;
-    clearInterval(id?: number): void;
-    clearTimeout(id?: number): void;
+    clearInterval(id: number | undefined): void;
+    clearTimeout(id: number | undefined): void;
     createImageBitmap(image: ImageBitmapSource, options?: ImageBitmapOptions): Promise<ImageBitmap>;
     createImageBitmap(image: ImageBitmapSource, sx: number, sy: number, sw: number, sh: number, options?: ImageBitmapOptions): Promise<ImageBitmap>;
     fetch(input: RequestInfo | URL, init?: RequestInit): Promise<Response>;
@@ -17953,8 +17953,8 @@ declare var origin: string;
 declare var performance: Performance;
 declare function atob(data: string): string;
 declare function btoa(data: string): string;
-declare function clearInterval(id?: number): void;
-declare function clearTimeout(id?: number): void;
+declare function clearInterval(id: number | undefined): void;
+declare function clearTimeout(id: number | undefined): void;
 declare function createImageBitmap(image: ImageBitmapSource, options?: ImageBitmapOptions): Promise<ImageBitmap>;
 declare function createImageBitmap(image: ImageBitmapSource, sx: number, sy: number, sw: number, sh: number, options?: ImageBitmapOptions): Promise<ImageBitmap>;
 declare function fetch(input: RequestInfo | URL, init?: RequestInit): Promise<Response>;
diff --git a/baselines/serviceworker.generated.d.ts b/baselines/serviceworker.generated.d.ts
index 1a0a79f0d..3153e67c8 100644
--- a/baselines/serviceworker.generated.d.ts
+++ b/baselines/serviceworker.generated.d.ts
@@ -5114,8 +5114,8 @@ interface WindowOrWorkerGlobalScope {
     readonly performance: Performance;
     atob(data: string): string;
     btoa(data: string): string;
-    clearInterval(id?: number): void;
-    clearTimeout(id?: number): void;
+    clearInterval(id: number | undefined): void;
+    clearTimeout(id: number | undefined): void;
     createImageBitmap(image: ImageBitmapSource, options?: ImageBitmapOptions): Promise<ImageBitmap>;
     createImageBitmap(image: ImageBitmapSource, sx: number, sy: number, sw: number, sh: number, options?: ImageBitmapOptions): Promise<ImageBitmap>;
     fetch(input: RequestInfo | URL, init?: RequestInit): Promise<Response>;
@@ -5484,8 +5484,8 @@ declare var origin: string;
 declare var performance: Performance;
 declare function atob(data: string): string;
 declare function btoa(data: string): string;
-declare function clearInterval(id?: number): void;
-declare function clearTimeout(id?: number): void;
+declare function clearInterval(id: number | undefined): void;
+declare function clearTimeout(id: number | undefined): void;
 declare function createImageBitmap(image: ImageBitmapSource, options?: ImageBitmapOptions): Promise<ImageBitmap>;
 declare function createImageBitmap(image: ImageBitmapSource, sx: number, sy: number, sw: number, sh: number, options?: ImageBitmapOptions): Promise<ImageBitmap>;
 declare function fetch(input: RequestInfo | URL, init?: RequestInit): Promise<Response>;
diff --git a/baselines/sharedworker.generated.d.ts b/baselines/sharedworker.generated.d.ts
index fe9307b2d..d16268926 100644
--- a/baselines/sharedworker.generated.d.ts
+++ b/baselines/sharedworker.generated.d.ts
@@ -4968,8 +4968,8 @@ interface WindowOrWorkerGlobalScope {
     readonly performance: Performance;
     atob(data: string): string;
     btoa(data: string): string;
-    clearInterval(id?: number): void;
-    clearTimeout(id?: number): void;
+    clearInterval(id: number | undefined): void;
+    clearTimeout(id: number | undefined): void;
     createImageBitmap(image: ImageBitmapSource, options?: ImageBitmapOptions): Promise<ImageBitmap>;
     createImageBitmap(image: ImageBitmapSource, sx: number, sy: number, sw: number, sh: number, options?: ImageBitmapOptions): Promise<ImageBitmap>;
     fetch(input: RequestInfo | URL, init?: RequestInit): Promise<Response>;
@@ -5500,8 +5500,8 @@ declare var origin: string;
 declare var performance: Performance;
 declare function atob(data: string): string;
 declare function btoa(data: string): string;
-declare function clearInterval(id?: number): void;
-declare function clearTimeout(id?: number): void;
+declare function clearInterval(id: number | undefined): void;
+declare function clearTimeout(id: number | undefined): void;
 declare function createImageBitmap(image: ImageBitmapSource, options?: ImageBitmapOptions): Promise<ImageBitmap>;
 declare function createImageBitmap(image: ImageBitmapSource, sx: number, sy: number, sw: number, sh: number, options?: ImageBitmapOptions): Promise<ImageBitmap>;
 declare function fetch(input: RequestInfo | URL, init?: RequestInit): Promise<Response>;
diff --git a/baselines/webworker.generated.d.ts b/baselines/webworker.generated.d.ts
index 63a02b060..ab3f32e82 100644
--- a/baselines/webworker.generated.d.ts
+++ b/baselines/webworker.generated.d.ts
@@ -5248,8 +5248,8 @@ interface WindowOrWorkerGlobalScope {
     readonly performance: Performance;
     atob(data: string): string;
     btoa(data: string): string;
-    clearInterval(id?: number): void;
-    clearTimeout(id?: number): void;
+    clearInterval(id: number | undefined): void;
+    clearTimeout(id: number | undefined): void;
     createImageBitmap(image: ImageBitmapSource, options?: ImageBitmapOptions): Promise<ImageBitmap>;
     createImageBitmap(image: ImageBitmapSource, sx: number, sy: number, sw: number, sh: number, options?: ImageBitmapOptions): Promise<ImageBitmap>;
     fetch(input: RequestInfo | URL, init?: RequestInit): Promise<Response>;
@@ -5788,8 +5788,8 @@ declare var origin: string;
 declare var performance: Performance;
 declare function atob(data: string): string;
 declare function btoa(data: string): string;
-declare function clearInterval(id?: number): void;
-declare function clearTimeout(id?: number): void;
+declare function clearInterval(id: number | undefined): void;
+declare function clearTimeout(id: number | undefined): void;
 declare function createImageBitmap(image: ImageBitmapSource, options?: ImageBitmapOptions): Promise<ImageBitmap>;
 declare function createImageBitmap(image: ImageBitmapSource, sx: number, sy: number, sw: number, sh: number, options?: ImageBitmapOptions): Promise<ImageBitmap>;
 declare function fetch(input: RequestInfo | URL, init?: RequestInit): Promise<Response>;
diff --git a/inputfiles/overridingTypes.jsonc b/inputfiles/overridingTypes.jsonc
index 2d52dcf90..52e5b2c44 100644
--- a/inputfiles/overridingTypes.jsonc
+++ b/inputfiles/overridingTypes.jsonc
@@ -218,6 +218,36 @@
                         }
                     }
                 }
+            },
+            "WindowOrWorkerGlobalScope": {
+                "methods": {
+                    "method": {
+                        "clearInterval": {
+                            "signature": {
+                                "0": {
+                                    "param": [
+                                        {
+                                            "name": "id",
+                                            "overrideType": "number | undefined"
+                                        }
+                                    ]
+                                }
+                            }
+                        },
+                        "clearTimeout": {
+                            "signature": {
+                                "0": {
+                                    "param": [
+                                        {
+                                            "name": "id",
+                                            "overrideType": "number | undefined"
+                                        }
+                                    ]
+                                }
+                            }
+                        }
+                    }
+                }
             }
         }
     },