diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index 97834d1cc..628d459a5 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -2576,8 +2576,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -44819,6 +44819,7 @@ type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
 type HTMLOrSVGImageElement = HTMLImageElement | SVGImageElement;
 type HTMLOrSVGScriptElement = HTMLScriptElement | SVGScriptElement;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -44856,6 +44857,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | MediaSourceHandle | ReadableStream | WritableStream | TransformStream | AudioData | VideoFrame | RTCDataChannel | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array<ArrayBufferLike> | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type VibratePattern = number | number[];
 type WindowProxy = Window;
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
diff --git a/baselines/serviceworker.generated.d.ts b/baselines/serviceworker.generated.d.ts
index 31e1f571c..7e68f1f1b 100644
--- a/baselines/serviceworker.generated.d.ts
+++ b/baselines/serviceworker.generated.d.ts
@@ -973,8 +973,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -13565,6 +13565,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -13587,6 +13588,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | ReadableStream | WritableStream | TransformStream | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array<ArrayBufferLike> | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type BinaryType = "arraybuffer" | "blob";
 type CSSMathOperator = "clamp" | "invert" | "max" | "min" | "negate" | "product" | "sum";
diff --git a/baselines/sharedworker.generated.d.ts b/baselines/sharedworker.generated.d.ts
index 2ded66418..54aecc3cf 100644
--- a/baselines/sharedworker.generated.d.ts
+++ b/baselines/sharedworker.generated.d.ts
@@ -903,8 +903,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -13254,6 +13254,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -13275,6 +13276,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | ReadableStream | WritableStream | TransformStream | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array<ArrayBufferLike> | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type BinaryType = "arraybuffer" | "blob";
 type CSSMathOperator = "clamp" | "invert" | "max" | "min" | "negate" | "product" | "sum";
diff --git a/baselines/ts5.5/dom.generated.d.ts b/baselines/ts5.5/dom.generated.d.ts
index e95d4d669..905c90e9a 100644
--- a/baselines/ts5.5/dom.generated.d.ts
+++ b/baselines/ts5.5/dom.generated.d.ts
@@ -2573,8 +2573,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -44793,6 +44793,7 @@ type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
 type HTMLOrSVGImageElement = HTMLImageElement | SVGImageElement;
 type HTMLOrSVGScriptElement = HTMLScriptElement | SVGScriptElement;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -44830,6 +44831,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | MediaSourceHandle | ReadableStream | WritableStream | TransformStream | AudioData | VideoFrame | RTCDataChannel | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type VibratePattern = number | number[];
 type WindowProxy = Window;
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
diff --git a/baselines/ts5.5/serviceworker.generated.d.ts b/baselines/ts5.5/serviceworker.generated.d.ts
index 9a530f4c0..c466cfa5e 100644
--- a/baselines/ts5.5/serviceworker.generated.d.ts
+++ b/baselines/ts5.5/serviceworker.generated.d.ts
@@ -970,8 +970,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -13562,6 +13562,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -13584,6 +13585,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | ReadableStream | WritableStream | TransformStream | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type BinaryType = "arraybuffer" | "blob";
 type CSSMathOperator = "clamp" | "invert" | "max" | "min" | "negate" | "product" | "sum";
diff --git a/baselines/ts5.5/sharedworker.generated.d.ts b/baselines/ts5.5/sharedworker.generated.d.ts
index aa2813d99..06f9075f7 100644
--- a/baselines/ts5.5/sharedworker.generated.d.ts
+++ b/baselines/ts5.5/sharedworker.generated.d.ts
@@ -900,8 +900,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -13251,6 +13251,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -13272,6 +13273,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | ReadableStream | WritableStream | TransformStream | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type BinaryType = "arraybuffer" | "blob";
 type CSSMathOperator = "clamp" | "invert" | "max" | "min" | "negate" | "product" | "sum";
diff --git a/baselines/ts5.5/webworker.generated.d.ts b/baselines/ts5.5/webworker.generated.d.ts
index 311d92117..d344ef6cc 100644
--- a/baselines/ts5.5/webworker.generated.d.ts
+++ b/baselines/ts5.5/webworker.generated.d.ts
@@ -1121,8 +1121,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -15376,6 +15376,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -15399,6 +15400,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | MediaSourceHandle | ReadableStream | WritableStream | TransformStream | AudioData | VideoFrame | RTCDataChannel | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type AacBitstreamFormat = "aac" | "adts";
 type AlphaOption = "discard" | "keep";
diff --git a/baselines/ts5.6/dom.generated.d.ts b/baselines/ts5.6/dom.generated.d.ts
index d502ea70d..756583abf 100644
--- a/baselines/ts5.6/dom.generated.d.ts
+++ b/baselines/ts5.6/dom.generated.d.ts
@@ -2573,8 +2573,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -44816,6 +44816,7 @@ type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
 type HTMLOrSVGImageElement = HTMLImageElement | SVGImageElement;
 type HTMLOrSVGScriptElement = HTMLScriptElement | SVGScriptElement;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -44853,6 +44854,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | MediaSourceHandle | ReadableStream | WritableStream | TransformStream | AudioData | VideoFrame | RTCDataChannel | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type VibratePattern = number | number[];
 type WindowProxy = Window;
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
diff --git a/baselines/ts5.6/serviceworker.generated.d.ts b/baselines/ts5.6/serviceworker.generated.d.ts
index 9a530f4c0..c466cfa5e 100644
--- a/baselines/ts5.6/serviceworker.generated.d.ts
+++ b/baselines/ts5.6/serviceworker.generated.d.ts
@@ -970,8 +970,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -13562,6 +13562,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -13584,6 +13585,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | ReadableStream | WritableStream | TransformStream | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type BinaryType = "arraybuffer" | "blob";
 type CSSMathOperator = "clamp" | "invert" | "max" | "min" | "negate" | "product" | "sum";
diff --git a/baselines/ts5.6/sharedworker.generated.d.ts b/baselines/ts5.6/sharedworker.generated.d.ts
index aa2813d99..06f9075f7 100644
--- a/baselines/ts5.6/sharedworker.generated.d.ts
+++ b/baselines/ts5.6/sharedworker.generated.d.ts
@@ -900,8 +900,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -13251,6 +13251,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -13272,6 +13273,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | ReadableStream | WritableStream | TransformStream | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type BinaryType = "arraybuffer" | "blob";
 type CSSMathOperator = "clamp" | "invert" | "max" | "min" | "negate" | "product" | "sum";
diff --git a/baselines/ts5.6/webworker.generated.d.ts b/baselines/ts5.6/webworker.generated.d.ts
index 311d92117..d344ef6cc 100644
--- a/baselines/ts5.6/webworker.generated.d.ts
+++ b/baselines/ts5.6/webworker.generated.d.ts
@@ -1121,8 +1121,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -15376,6 +15376,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -15399,6 +15400,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | MediaSourceHandle | ReadableStream | WritableStream | TransformStream | AudioData | VideoFrame | RTCDataChannel | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type AacBitstreamFormat = "aac" | "adts";
 type AlphaOption = "discard" | "keep";
diff --git a/baselines/ts5.9/dom.generated.d.ts b/baselines/ts5.9/dom.generated.d.ts
index 93c9798d6..686d3c908 100644
--- a/baselines/ts5.9/dom.generated.d.ts
+++ b/baselines/ts5.9/dom.generated.d.ts
@@ -2573,8 +2573,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -44816,6 +44816,7 @@ type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
 type HTMLOrSVGImageElement = HTMLImageElement | SVGImageElement;
 type HTMLOrSVGScriptElement = HTMLScriptElement | SVGScriptElement;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -44853,6 +44854,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | MediaSourceHandle | ReadableStream | WritableStream | TransformStream | AudioData | VideoFrame | RTCDataChannel | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array<ArrayBufferLike> | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type VibratePattern = number | number[];
 type WindowProxy = Window;
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
diff --git a/baselines/ts5.9/serviceworker.generated.d.ts b/baselines/ts5.9/serviceworker.generated.d.ts
index cdb481f8e..851ec6deb 100644
--- a/baselines/ts5.9/serviceworker.generated.d.ts
+++ b/baselines/ts5.9/serviceworker.generated.d.ts
@@ -970,8 +970,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -13562,6 +13562,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -13584,6 +13585,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | ReadableStream | WritableStream | TransformStream | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array<ArrayBufferLike> | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type BinaryType = "arraybuffer" | "blob";
 type CSSMathOperator = "clamp" | "invert" | "max" | "min" | "negate" | "product" | "sum";
diff --git a/baselines/ts5.9/sharedworker.generated.d.ts b/baselines/ts5.9/sharedworker.generated.d.ts
index b84b2d8c0..0be78c7e5 100644
--- a/baselines/ts5.9/sharedworker.generated.d.ts
+++ b/baselines/ts5.9/sharedworker.generated.d.ts
@@ -900,8 +900,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -13251,6 +13251,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -13272,6 +13273,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | ReadableStream | WritableStream | TransformStream | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array<ArrayBufferLike> | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type BinaryType = "arraybuffer" | "blob";
 type CSSMathOperator = "clamp" | "invert" | "max" | "min" | "negate" | "product" | "sum";
diff --git a/baselines/ts5.9/webworker.generated.d.ts b/baselines/ts5.9/webworker.generated.d.ts
index e5c471811..3279683a0 100644
--- a/baselines/ts5.9/webworker.generated.d.ts
+++ b/baselines/ts5.9/webworker.generated.d.ts
@@ -1121,8 +1121,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -15376,6 +15376,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -15399,6 +15400,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | MediaSourceHandle | ReadableStream | WritableStream | TransformStream | AudioData | VideoFrame | RTCDataChannel | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array<ArrayBufferLike> | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type AacBitstreamFormat = "aac" | "adts";
 type AlphaOption = "discard" | "keep";
diff --git a/baselines/webworker.generated.d.ts b/baselines/webworker.generated.d.ts
index 40440f32c..a681b5360 100644
--- a/baselines/webworker.generated.d.ts
+++ b/baselines/webworker.generated.d.ts
@@ -1124,8 +1124,8 @@ interface RequestInit {
     integrity?: string;
     /** A boolean to set request's keepalive. */
     keepalive?: boolean;
-    /** A string to set request's method. */
-    method?: string;
+    /** A string to set request's method. Defaults to "GET". */
+    method?: HTTPMethod;
     /** A string to indicate whether the request will use CORS, or will be restricted to same-origin URLs. Sets request's mode. */
     mode?: RequestMode;
     priority?: RequestPriority;
@@ -15379,6 +15379,7 @@ type GPUSize64 = number;
 type GPUSize64Out = number;
 type GPUStencilValue = number;
 type GPUTextureUsageFlags = number;
+type HTTPMethod = (UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {};
 type HashAlgorithmIdentifier = AlgorithmIdentifier;
 type HeadersInit = [string, string][] | Record<string, string> | Headers;
 type IDBValidKey = number | string | Date | BufferSource | IDBValidKey[];
@@ -15402,6 +15403,7 @@ type TimerHandler = string | Function;
 type Transferable = OffscreenCanvas | ImageBitmap | MessagePort | MediaSourceHandle | ReadableStream | WritableStream | TransformStream | AudioData | VideoFrame | RTCDataChannel | ArrayBuffer;
 type URLPatternInput = string | URLPatternInit;
 type Uint32List = Uint32Array<ArrayBufferLike> | GLuint[];
+type UppercaseHTTPMethod = "GET" | "HEAD" | "POST" | "PUT" | "DELETE" | "CONNECT" | "OPTIONS" | "TRACE" | "PATCH" | "QUERY";
 type XMLHttpRequestBodyInit = Blob | BufferSource | FormData | URLSearchParams | string;
 type AacBitstreamFormat = "aac" | "adts";
 type AlphaOption = "discard" | "keep";
diff --git a/inputfiles/addedTypes.jsonc b/inputfiles/addedTypes.jsonc
index 64861d798..675f0420c 100644
--- a/inputfiles/addedTypes.jsonc
+++ b/inputfiles/addedTypes.jsonc
@@ -502,6 +502,14 @@
                 // Full spec at https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#autofill.
                 "name": "AutoFill",
                 "overrideType": "AutoFillBase | `${OptionalPrefixToken<AutoFillSection>}${OptionalPrefixToken<AutoFillAddressKind>}${AutoFillField}${OptionalPostfixToken<AutoFillCredentialField>}`"
+            },
+            {
+                "name": "UppercaseHTTPMethod",
+                "overrideType": "\"GET\" | \"HEAD\" | \"POST\" | \"PUT\" | \"DELETE\" | \"CONNECT\" | \"OPTIONS\" | \"TRACE\" | \"PATCH\" | \"QUERY\""
+            },
+            {
+                "name": "HTTPMethod",
+                "overrideType": "(UppercaseHTTPMethod | Lowercase<UppercaseHTTPMethod>) & {}"
             }
         ]
     }
diff --git a/inputfiles/idl/fetch.commentmap.json b/inputfiles/idl/fetch.commentmap.json
index a8b5765d7..6a529be6c 100644
--- a/inputfiles/idl/fetch.commentmap.json
+++ b/inputfiles/idl/fetch.commentmap.json
@@ -1,5 +1,5 @@
 {
-    "requestinit-method": "A string to set request's method.",
+    "requestinit-method": "A string to set request's method. Defaults to \"GET\".",
     "requestinit-headers": "A Headers object, an object literal, or an array of two-item arrays to set request's headers.",
     "requestinit-body": "A BodyInit object or null to set request's body.",
     "requestinit-referrer": "A string whose value is a same-origin URL, \"about:client\", or the empty string, to set request's referrer.",
diff --git a/inputfiles/knownTypes.json b/inputfiles/knownTypes.json
index 3abf26035..a8a349fe5 100644
--- a/inputfiles/knownTypes.json
+++ b/inputfiles/knownTypes.json
@@ -30,6 +30,7 @@
         "HmacImportParams",
         "HmacKeyAlgorithm",
         "HmacKeyGenParams",
+        "HTTPMethod",
         "ImageBitmapRenderingContextSettings",
         "Keyframe",
         "NamedCurve",
@@ -58,6 +59,7 @@
         "RTCStatsType",
         "RTCTransportStats",
         "ValueTypeMap",
+        "UppercaseHTTPMethod",
         "VideoFacingModeEnum"
     ],
     "Worker": [
@@ -77,6 +79,7 @@
         "HkdfParams",
         "HmacImportParams",
         "HmacKeyGenParams",
+        "HTTPMethod",
         "ImageBitmapRenderingContextSettings",
         "NamedCurve",
         "Pbkdf2Params",
@@ -85,6 +88,7 @@
         "RsaKeyGenParams",
         "RsaOaepParams",
         "RsaPssParams",
+        "UppercaseHTTPMethod",
         "ValueTypeMap"
     ],
     "Worklet": [
diff --git a/inputfiles/overridingTypes.jsonc b/inputfiles/overridingTypes.jsonc
index c6e2832d5..87c754903 100644
--- a/inputfiles/overridingTypes.jsonc
+++ b/inputfiles/overridingTypes.jsonc
@@ -3058,6 +3058,9 @@
                     "member": {
                         "window": {
                             "overrideType": "null"
+                        },
+                        "method": {
+                            "overrideType": "HTTPMethod"
                         }
                     }
                 }