From 22a925972a6af8e2c1e2c5464a742f4f934da7d3 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Wed, 17 Jul 2024 17:17:34 +0200
Subject: [PATCH 01/18] feat(webidl): add async iterable converter

---
 ext/fetch/22_body.js     |   7 +++
 ext/web/06_streams.js    |  26 +++------
 ext/webidl/00_webidl.js  | 112 ++++++++++++++++++++++++++++++++++++++-
 ext/webidl/internal.d.ts |  21 ++++++++
 4 files changed, 146 insertions(+), 20 deletions(-)

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index e9d493658698c6..d1123704c2ccc8 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -32,6 +32,7 @@ const {
   TypedArrayPrototypeSlice,
   TypeError,
   Uint8Array,
+  SymbolAsyncIterator,
 } = primordials;
 
 import * as webidl from "ext:deno_webidl/00_webidl.js";
@@ -58,6 +59,7 @@ import {
   readableStreamTee,
   readableStreamThrowIfErrored,
 } from "ext:deno_web/06_streams.js";
+import { converters, createAsyncIterableConverter } from "../webidl/00_webidl";
 
 /**
  * @param {Uint8Array | string} chunk
@@ -445,6 +447,8 @@ function extractBody(object) {
     if (object.locked || isReadableStreamDisturbed(object)) {
       throw new TypeError("ReadableStream is locked or disturbed");
     }
+  } else if (object[SymbolAsyncIterator] !== undefined) {
+    stream = ReadableStream.from(object.value);
   }
   if (typeof source === "string") {
     // WARNING: this deviates from spec (expects length to be set)
@@ -462,6 +466,8 @@ function extractBody(object) {
   return { body, contentType };
 }
 
+webidl.converters["async iterable<Uint8Array>"] = createAsyncIterableConverter(webidl.converters.Uint8Array);
+
 webidl.converters["BodyInit_DOMString"] = (V, prefix, context, opts) => {
   // Union for (ReadableStream or Blob or ArrayBufferView or ArrayBuffer or FormData or URLSearchParams or USVString)
   if (ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, V)) {
@@ -480,6 +486,7 @@ webidl.converters["BodyInit_DOMString"] = (V, prefix, context, opts) => {
     if (ArrayBufferIsView(V)) {
       return webidl.converters["ArrayBufferView"](V, prefix, context, opts);
     }
+    return webidl.converters["async iterable<Uint8Array>"](V, prefix, context, opts);
   }
   // BodyInit conversion is passed to extractBody(), which calls core.encode().
   // core.encode() will UTF-8 encode strings with replacement, being equivalent to the USV normalization.
diff --git a/ext/web/06_streams.js b/ext/web/06_streams.js
index d3de24363798c4..050b136697f202 100644
--- a/ext/web/06_streams.js
+++ b/ext/web/06_streams.js
@@ -5196,21 +5196,17 @@ class ReadableStream {
   }
 
   static from(asyncIterable) {
+    const prefix = "Failed to execute 'ReadableStream.from'";
     webidl.requiredArguments(
       arguments.length,
       1,
-      "Failed to execute 'ReadableStream.from'",
+      prefix,
     );
-    asyncIterable = webidl.converters.any(asyncIterable);
-
-    const iterator = getAsyncOrSyncIterator(asyncIterable);
+    asyncIterable = webidl.converters["async iterable<any>"](asyncIterable, prefix, "Argument 1");
 
     const stream = createReadableStream(noop, async () => {
       // deno-lint-ignore prefer-primordials
-      const res = await iterator.next();
-      if (!isObject(res)) {
-        throw new TypeError("iterator.next value is not an object");
-      }
+      const res = await asyncIterable.next();
       if (res.done) {
         readableStreamDefaultControllerClose(stream[_controller]);
       } else {
@@ -5220,17 +5216,7 @@ class ReadableStream {
         );
       }
     }, async (reason) => {
-      if (iterator.return == null) {
-        return undefined;
-      } else {
-        // deno-lint-ignore prefer-primordials
-        const res = await iterator.return(reason);
-        if (!isObject(res)) {
-          throw new TypeError("iterator.return value is not an object");
-        } else {
-          return undefined;
-        }
-      }
+      await asyncIterable.return(reason);
     }, 0);
     return stream;
   }
@@ -6890,6 +6876,8 @@ webidl.converters.StreamPipeOptions = webidl
     { key: "signal", converter: webidl.converters.AbortSignal },
   ]);
 
+webidl.converters["async iterable<any>"] = webidl.createAsyncIterableConverter(webidl.converters.any);
+
 internals.resourceForReadableStream = resourceForReadableStream;
 
 export {
diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index 9ea2200f333af7..79efbc2b155715 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -6,7 +6,7 @@
 
 /// <reference path="../../core/internal.d.ts" />
 
-import { core, primordials } from "ext:core/mod.js";
+import { core, primordials, internals } from "ext:core/mod.js";
 const {
   isArrayBuffer,
   isDataView,
@@ -26,6 +26,7 @@ const {
   Float32Array,
   Float64Array,
   FunctionPrototypeBind,
+  FunctionPrototypeCall,
   Int16Array,
   Int32Array,
   Int8Array,
@@ -77,6 +78,7 @@ const {
   StringPrototypeToWellFormed,
   Symbol,
   SymbolIterator,
+  SymbolAsyncIterator,
   SymbolToStringTag,
   TypedArrayPrototypeGetBuffer,
   TypedArrayPrototypeGetSymbolToStringTag,
@@ -919,6 +921,113 @@ function createSequenceConverter(converter) {
   };
 }
 
+// Ref: https://tc39.es/ecma262/#sec-getiterator, modified to not call the iterator
+function getIteratorAsync(obj) {
+  const method = obj[SymbolAsyncIterator];
+  if (method === undefined) {
+    const syncMethod = obj[SymbolIterator];
+    if (syncMethod === undefined) {
+      throw new TypeError("No iterator found");
+    }
+    return syncMethod;
+  } else {
+    return method;
+  }
+}
+
+function CreateAsyncFromSyncIterator(iter) {
+  return {
+    async next() {
+      return iter.next();
+    }
+  }
+}
+
+function createAsyncIterableConverter(converter) {
+  return function (
+    V,
+    prefix = undefined,
+    context = undefined,
+    opts = { __proto__: null },
+  ) {
+    if (type(V) !== "Object") {
+      throw makeException(
+        TypeError,
+        "can not be converted to async iterable.",
+        prefix,
+        context,
+      );
+    }
+
+    const iter = getIteratorAsync(V);
+
+    let iterator;
+    return {
+      async next() {
+        if (!iterator) {
+          if (V[SymbolIterator]) {
+            iterator = CreateAsyncFromSyncIterator(FunctionPrototypeCall(iter, V));
+          } else {
+            iterator = FunctionPrototypeCall(iter, V);
+          }
+        }
+
+        const iterResult = await iterator.next();
+        if (type(iterResult) !== "Object") {
+          throw makeException(
+            TypeError,
+            "can not be converted to async iterable.",
+            prefix,
+            context,
+          );
+        }
+
+        if (iterResult.done) {
+          return { done: true };
+        }
+
+        const iterValue = converter(
+          iterResult.value,
+          prefix,
+          context,
+          opts,
+        );
+
+        return { done: false, value: iterValue };
+      },
+      async return(reason) {
+        if (!iterator) {
+          if (V[SymbolIterator]) {
+            iterator = CreateAsyncFromSyncIterator(FunctionPrototypeCall(iter, V));
+          } else {
+            iterator = FunctionPrototypeCall(iter, V);
+          }
+        }
+
+        if (iterator.return === undefined) {
+          return undefined;
+        }
+
+        const returnPromiseResult = await iterator.return(reason);
+        if (type(returnPromiseResult) !== "Object") {
+          throw makeException(
+            TypeError,
+            "can not be converted to async iterable.",
+            prefix,
+            context,
+          );
+        }
+
+        return undefined;
+      },
+      [SymbolAsyncIterator]() {
+        return this;
+      },
+      value: V,
+    };
+  };
+}
+
 function createRecordConverter(keyConverter, valueConverter) {
   return (V, prefix, context, opts) => {
     if (type(V) !== "Object") {
@@ -1298,6 +1407,7 @@ export {
   createPromiseConverter,
   createRecordConverter,
   createSequenceConverter,
+  createAsyncIterableConverter,
   illegalConstructor,
   invokeCallbackFunction,
   makeException,
diff --git a/ext/webidl/internal.d.ts b/ext/webidl/internal.d.ts
index 1ce45463ecc37e..d9266f5f548a3c 100644
--- a/ext/webidl/internal.d.ts
+++ b/ext/webidl/internal.d.ts
@@ -438,6 +438,27 @@ declare module "ext:deno_webidl/00_webidl.js" {
     opts?: any,
   ) => T[];
 
+  /**
+   * Create a converter that converts an async iterable of the inner type.
+   */
+  function createAsyncIterableConverter<V, T>(
+    converter: (
+      v: V,
+      prefix?: string,
+      context?: string,
+      opts?: any,
+    ) => T,
+  ): (
+    v: any,
+    prefix?: string,
+    context?: string,
+    opts?: any,
+  ) => ConvertedAsyncIterable<V, T>;
+
+  interface ConvertedAsyncIterable<V, T> extends AsyncIterableIterator<T> {
+    value: V;
+  }
+
   /**
    * Create a converter that converts a Promise of the inner type.
    */

From 0f80a1c00576742b66d6462980132b0fa7407d06 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Wed, 17 Jul 2024 17:19:16 +0200
Subject: [PATCH 02/18] fmt

---
 ext/fetch/22_body.js    | 11 ++++++++---
 ext/web/06_streams.js   | 10 ++++++++--
 ext/webidl/00_webidl.js | 16 ++++++++++------
 3 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index d1123704c2ccc8..9ae5862a284b94 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -59,7 +59,6 @@ import {
   readableStreamTee,
   readableStreamThrowIfErrored,
 } from "ext:deno_web/06_streams.js";
-import { converters, createAsyncIterableConverter } from "../webidl/00_webidl";
 
 /**
  * @param {Uint8Array | string} chunk
@@ -466,7 +465,8 @@ function extractBody(object) {
   return { body, contentType };
 }
 
-webidl.converters["async iterable<Uint8Array>"] = createAsyncIterableConverter(webidl.converters.Uint8Array);
+webidl.converters["async iterable<Uint8Array>"] = webidl
+  .createAsyncIterableConverter(webidl.converters.Uint8Array);
 
 webidl.converters["BodyInit_DOMString"] = (V, prefix, context, opts) => {
   // Union for (ReadableStream or Blob or ArrayBufferView or ArrayBuffer or FormData or URLSearchParams or USVString)
@@ -486,7 +486,12 @@ webidl.converters["BodyInit_DOMString"] = (V, prefix, context, opts) => {
     if (ArrayBufferIsView(V)) {
       return webidl.converters["ArrayBufferView"](V, prefix, context, opts);
     }
-    return webidl.converters["async iterable<Uint8Array>"](V, prefix, context, opts);
+    return webidl.converters["async iterable<Uint8Array>"](
+      V,
+      prefix,
+      context,
+      opts,
+    );
   }
   // BodyInit conversion is passed to extractBody(), which calls core.encode().
   // core.encode() will UTF-8 encode strings with replacement, being equivalent to the USV normalization.
diff --git a/ext/web/06_streams.js b/ext/web/06_streams.js
index 050b136697f202..2d0f776b5dc0f5 100644
--- a/ext/web/06_streams.js
+++ b/ext/web/06_streams.js
@@ -5202,7 +5202,11 @@ class ReadableStream {
       1,
       prefix,
     );
-    asyncIterable = webidl.converters["async iterable<any>"](asyncIterable, prefix, "Argument 1");
+    asyncIterable = webidl.converters["async iterable<any>"](
+      asyncIterable,
+      prefix,
+      "Argument 1",
+    );
 
     const stream = createReadableStream(noop, async () => {
       // deno-lint-ignore prefer-primordials
@@ -6876,7 +6880,9 @@ webidl.converters.StreamPipeOptions = webidl
     { key: "signal", converter: webidl.converters.AbortSignal },
   ]);
 
-webidl.converters["async iterable<any>"] = webidl.createAsyncIterableConverter(webidl.converters.any);
+webidl.converters["async iterable<any>"] = webidl.createAsyncIterableConverter(
+  webidl.converters.any,
+);
 
 internals.resourceForReadableStream = resourceForReadableStream;
 
diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index 79efbc2b155715..0adc4b96a58f1e 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -6,7 +6,7 @@
 
 /// <reference path="../../core/internal.d.ts" />
 
-import { core, primordials, internals } from "ext:core/mod.js";
+import { core, internals, primordials } from "ext:core/mod.js";
 const {
   isArrayBuffer,
   isDataView,
@@ -939,8 +939,8 @@ function CreateAsyncFromSyncIterator(iter) {
   return {
     async next() {
       return iter.next();
-    }
-  }
+    },
+  };
 }
 
 function createAsyncIterableConverter(converter) {
@@ -966,7 +966,9 @@ function createAsyncIterableConverter(converter) {
       async next() {
         if (!iterator) {
           if (V[SymbolIterator]) {
-            iterator = CreateAsyncFromSyncIterator(FunctionPrototypeCall(iter, V));
+            iterator = CreateAsyncFromSyncIterator(
+              FunctionPrototypeCall(iter, V),
+            );
           } else {
             iterator = FunctionPrototypeCall(iter, V);
           }
@@ -998,7 +1000,9 @@ function createAsyncIterableConverter(converter) {
       async return(reason) {
         if (!iterator) {
           if (V[SymbolIterator]) {
-            iterator = CreateAsyncFromSyncIterator(FunctionPrototypeCall(iter, V));
+            iterator = CreateAsyncFromSyncIterator(
+              FunctionPrototypeCall(iter, V),
+            );
           } else {
             iterator = FunctionPrototypeCall(iter, V);
           }
@@ -1399,6 +1403,7 @@ export {
   brand,
   configureInterface,
   converters,
+  createAsyncIterableConverter,
   createBranded,
   createDictionaryConverter,
   createEnumConverter,
@@ -1407,7 +1412,6 @@ export {
   createPromiseConverter,
   createRecordConverter,
   createSequenceConverter,
-  createAsyncIterableConverter,
   illegalConstructor,
   invokeCallbackFunction,
   makeException,

From d746a44b26a862c906532a0bf233ff5d504c41ef Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Wed, 17 Jul 2024 17:27:51 +0200
Subject: [PATCH 03/18] fix

---
 ext/fetch/22_body.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index 9ae5862a284b94..8771b80bd8ebed 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -447,7 +447,7 @@ function extractBody(object) {
       throw new TypeError("ReadableStream is locked or disturbed");
     }
   } else if (object[SymbolAsyncIterator] !== undefined) {
-    stream = ReadableStream.from(object.value);
+    stream = ReadableStream.from(object);
   }
   if (typeof source === "string") {
     // WARNING: this deviates from spec (expects length to be set)

From 3055ec23b252145116ec9de75e5bd70ac43a6bb4 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Wed, 17 Jul 2024 17:31:14 +0200
Subject: [PATCH 04/18] fix

---
 ext/fetch/22_body.js | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index 8771b80bd8ebed..c660942e413900 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -441,13 +441,15 @@ function extractBody(object) {
     // deno-lint-ignore prefer-primordials
     source = object.toString();
     contentType = "application/x-www-form-urlencoded;charset=UTF-8";
-  } else if (ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, object)) {
-    stream = object;
-    if (object.locked || isReadableStreamDisturbed(object)) {
-      throw new TypeError("ReadableStream is locked or disturbed");
-    }
   } else if (object[SymbolAsyncIterator] !== undefined) {
-    stream = ReadableStream.from(object);
+    if (ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, object)) {
+      stream = object;
+      if (object.locked || isReadableStreamDisturbed(object)) {
+        throw new TypeError("ReadableStream is locked or disturbed");
+      }
+    } else {
+      stream = ReadableStream.from(object);
+    }
   }
   if (typeof source === "string") {
     // WARNING: this deviates from spec (expects length to be set)

From 0c352e4945c025fa510d7cddd23d76780796e67d Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Wed, 17 Jul 2024 17:31:46 +0200
Subject: [PATCH 05/18] fix

---
 ext/fetch/22_body.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index c660942e413900..9cb251de622aa0 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -442,9 +442,9 @@ function extractBody(object) {
     source = object.toString();
     contentType = "application/x-www-form-urlencoded;charset=UTF-8";
   } else if (object[SymbolAsyncIterator] !== undefined) {
-    if (ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, object)) {
-      stream = object;
-      if (object.locked || isReadableStreamDisturbed(object)) {
+    if (ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, object.value)) {
+      stream = object.value;
+      if (object.value.locked || isReadableStreamDisturbed(object.value)) {
         throw new TypeError("ReadableStream is locked or disturbed");
       }
     } else {

From 075baead6b0e5fcf3b635b3725da8f39eae758de Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Wed, 17 Jul 2024 17:46:52 +0200
Subject: [PATCH 06/18] lint

---
 ext/web/06_streams.js   | 30 +-----------------------------
 ext/webidl/00_webidl.js |  6 +++++-
 2 files changed, 6 insertions(+), 30 deletions(-)

diff --git a/ext/web/06_streams.js b/ext/web/06_streams.js
index 2d0f776b5dc0f5..6b24221a35ba12 100644
--- a/ext/web/06_streams.js
+++ b/ext/web/06_streams.js
@@ -70,7 +70,6 @@ const {
   String,
   Symbol,
   SymbolAsyncIterator,
-  SymbolIterator,
   SymbolFor,
   TypeError,
   TypedArrayPrototypeGetBuffer,
@@ -5083,34 +5082,6 @@ function initializeCountSizeFunction(globalObject) {
   WeakMapPrototypeSet(countSizeFunctionWeakMap, globalObject, size);
 }
 
-// Ref: https://tc39.es/ecma262/#sec-getiterator
-function getAsyncOrSyncIterator(obj) {
-  let iterator;
-  if (obj[SymbolAsyncIterator] != null) {
-    iterator = obj[SymbolAsyncIterator]();
-    if (!isObject(iterator)) {
-      throw new TypeError(
-        "[Symbol.asyncIterator] returned a non-object value",
-      );
-    }
-  } else if (obj[SymbolIterator] != null) {
-    iterator = obj[SymbolIterator]();
-    if (!isObject(iterator)) {
-      throw new TypeError("[Symbol.iterator] returned a non-object value");
-    }
-  } else {
-    throw new TypeError("No iterator found");
-  }
-  if (typeof iterator.next !== "function") {
-    throw new TypeError("iterator.next is not a function");
-  }
-  return iterator;
-}
-
-function isObject(x) {
-  return (typeof x === "object" && x != null) || typeof x === "function";
-}
-
 const _resourceBacking = Symbol("[[resourceBacking]]");
 // This distinction exists to prevent unrefable streams being used in
 // regular fast streams that are unaware of refability
@@ -5220,6 +5191,7 @@ class ReadableStream {
         );
       }
     }, async (reason) => {
+      // deno-lint-ignore prefer-primordials
       await asyncIterable.return(reason);
     }, 0);
     return stream;
diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index 0adc4b96a58f1e..e6dbf950194d40 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -6,7 +6,7 @@
 
 /// <reference path="../../core/internal.d.ts" />
 
-import { core, internals, primordials } from "ext:core/mod.js";
+import { core, primordials } from "ext:core/mod.js";
 const {
   isArrayBuffer,
   isDataView,
@@ -937,7 +937,9 @@ function getIteratorAsync(obj) {
 
 function CreateAsyncFromSyncIterator(iter) {
   return {
+    // deno-lint-ignore require-await
     async next() {
+      // deno-lint-ignore prefer-primordials
       return iter.next();
     },
   };
@@ -974,6 +976,7 @@ function createAsyncIterableConverter(converter) {
           }
         }
 
+        // deno-lint-ignore prefer-primordials
         const iterResult = await iterator.next();
         if (type(iterResult) !== "Object") {
           throw makeException(
@@ -1012,6 +1015,7 @@ function createAsyncIterableConverter(converter) {
           return undefined;
         }
 
+        // deno-lint-ignore prefer-primordials
         const returnPromiseResult = await iterator.return(reason);
         if (type(returnPromiseResult) !== "Object") {
           throw makeException(

From 201ad3abfd7b066ce156e4b8a9ea56f2ba919ffb Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Thu, 18 Jul 2024 00:21:52 +0200
Subject: [PATCH 07/18] fix

---
 ext/fetch/22_body.js    | 5 ++---
 ext/webidl/00_webidl.js | 1 +
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index 9cb251de622aa0..19d7f6be28d2fa 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -472,9 +472,7 @@ webidl.converters["async iterable<Uint8Array>"] = webidl
 
 webidl.converters["BodyInit_DOMString"] = (V, prefix, context, opts) => {
   // Union for (ReadableStream or Blob or ArrayBufferView or ArrayBuffer or FormData or URLSearchParams or USVString)
-  if (ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, V)) {
-    return webidl.converters["ReadableStream"](V, prefix, context, opts);
-  } else if (ObjectPrototypeIsPrototypeOf(BlobPrototype, V)) {
+  if (ObjectPrototypeIsPrototypeOf(BlobPrototype, V)) {
     return webidl.converters["Blob"](V, prefix, context, opts);
   } else if (ObjectPrototypeIsPrototypeOf(FormDataPrototype, V)) {
     return webidl.converters["FormData"](V, prefix, context, opts);
@@ -488,6 +486,7 @@ webidl.converters["BodyInit_DOMString"] = (V, prefix, context, opts) => {
     if (ArrayBufferIsView(V)) {
       return webidl.converters["ArrayBufferView"](V, prefix, context, opts);
     }
+
     return webidl.converters["async iterable<Uint8Array>"](
       V,
       prefix,
diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index e6dbf950194d40..27ad1f3561c232 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -966,6 +966,7 @@ function createAsyncIterableConverter(converter) {
     let iterator;
     return {
       async next() {
+        console.error("foo", this);
         if (!iterator) {
           if (V[SymbolIterator]) {
             iterator = CreateAsyncFromSyncIterator(

From 494e88e5227d11ffcfc987a8dbdcd153fc5effdd Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Thu, 18 Jul 2024 16:17:32 +0200
Subject: [PATCH 08/18] fix and tests

---
 ext/fetch/22_body.js                 | 18 ++++-----
 ext/webidl/00_webidl.js              | 55 ++++++++++++++--------------
 tests/integration/node_unit_tests.rs |  1 +
 tests/unit/streams_test.ts           | 15 +++++++-
 tests/unit_node/fetch_test.ts        | 18 +++++++++
 tests/wpt/runner/expectation.json    | 10 ++++-
 6 files changed, 78 insertions(+), 39 deletions(-)
 create mode 100644 tests/unit_node/fetch_test.ts

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index 19d7f6be28d2fa..6e0e7276695b1d 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -441,15 +441,13 @@ function extractBody(object) {
     // deno-lint-ignore prefer-primordials
     source = object.toString();
     contentType = "application/x-www-form-urlencoded;charset=UTF-8";
-  } else if (object[SymbolAsyncIterator] !== undefined) {
-    if (ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, object.value)) {
-      stream = object.value;
-      if (object.value.locked || isReadableStreamDisturbed(object.value)) {
-        throw new TypeError("ReadableStream is locked or disturbed");
-      }
-    } else {
-      stream = ReadableStream.from(object);
+  } else if (ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, object)) {
+    stream = object;
+    if (object.locked || isReadableStreamDisturbed(object)) {
+      throw new TypeError("ReadableStream is locked or disturbed");
     }
+  } else if (object[SymbolAsyncIterator] !== undefined) {
+    stream = ReadableStream.from(object);
   }
   if (typeof source === "string") {
     // WARNING: this deviates from spec (expects length to be set)
@@ -472,7 +470,9 @@ webidl.converters["async iterable<Uint8Array>"] = webidl
 
 webidl.converters["BodyInit_DOMString"] = (V, prefix, context, opts) => {
   // Union for (ReadableStream or Blob or ArrayBufferView or ArrayBuffer or FormData or URLSearchParams or USVString)
-  if (ObjectPrototypeIsPrototypeOf(BlobPrototype, V)) {
+  if (ObjectPrototypeIsPrototypeOf(ReadableStreamPrototype, V)) {
+    return webidl.converters["ReadableStream"](V, prefix, context, opts);
+  } else if (ObjectPrototypeIsPrototypeOf(BlobPrototype, V)) {
     return webidl.converters["Blob"](V, prefix, context, opts);
   } else if (ObjectPrototypeIsPrototypeOf(FormDataPrototype, V)) {
     return webidl.converters["FormData"](V, prefix, context, opts);
diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index 27ad1f3561c232..f370a9a99f9ba6 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -921,17 +921,40 @@ function createSequenceConverter(converter) {
   };
 }
 
-// Ref: https://tc39.es/ecma262/#sec-getiterator, modified to not call the iterator
-function getIteratorAsync(obj) {
+// Ref: https://tc39.es/ecma262/#sec-getiterator
+function getIteratorAsync(obj, prefix, context) {
   const method = obj[SymbolAsyncIterator];
   if (method === undefined) {
     const syncMethod = obj[SymbolIterator];
+
     if (syncMethod === undefined) {
       throw new TypeError("No iterator found");
     }
-    return syncMethod;
+
+    const iter = FunctionPrototypeCall(syncMethod, obj);
+
+    if (type(iter) !== "Object") {
+      throw makeException(
+        TypeError,
+        "can not be converted to async iterable.",
+        prefix,
+        context,
+      );
+    }
+
+    return CreateAsyncFromSyncIterator(iter);
   } else {
-    return method;
+    const iter = FunctionPrototypeCall(method, obj);
+    if (type(iter) !== "Object") {
+      throw makeException(
+        TypeError,
+        "can not be converted to async iterable.",
+        prefix,
+        context,
+      );
+    }
+
+    return iter;
   }
 }
 
@@ -961,22 +984,10 @@ function createAsyncIterableConverter(converter) {
       );
     }
 
-    const iter = getIteratorAsync(V);
+    const iterator = getIteratorAsync(V, prefix, context);
 
-    let iterator;
     return {
       async next() {
-        console.error("foo", this);
-        if (!iterator) {
-          if (V[SymbolIterator]) {
-            iterator = CreateAsyncFromSyncIterator(
-              FunctionPrototypeCall(iter, V),
-            );
-          } else {
-            iterator = FunctionPrototypeCall(iter, V);
-          }
-        }
-
         // deno-lint-ignore prefer-primordials
         const iterResult = await iterator.next();
         if (type(iterResult) !== "Object") {
@@ -1002,16 +1013,6 @@ function createAsyncIterableConverter(converter) {
         return { done: false, value: iterValue };
       },
       async return(reason) {
-        if (!iterator) {
-          if (V[SymbolIterator]) {
-            iterator = CreateAsyncFromSyncIterator(
-              FunctionPrototypeCall(iter, V),
-            );
-          } else {
-            iterator = FunctionPrototypeCall(iter, V);
-          }
-        }
-
         if (iterator.return === undefined) {
           return undefined;
         }
diff --git a/tests/integration/node_unit_tests.rs b/tests/integration/node_unit_tests.rs
index 4f0b613788fa5e..e87f1cd2f8d3c1 100644
--- a/tests/integration/node_unit_tests.rs
+++ b/tests/integration/node_unit_tests.rs
@@ -71,6 +71,7 @@ util::unit_test_factory!(
     dgram_test,
     domain_test,
     fs_test,
+    fetch_test,
     http_test,
     http2_test,
     _randomBytes_test = internal / _randomBytes_test,
diff --git a/tests/unit/streams_test.ts b/tests/unit/streams_test.ts
index 80b45e6024af4b..c0adbda07c1ded 100644
--- a/tests/unit/streams_test.ts
+++ b/tests/unit/streams_test.ts
@@ -1,5 +1,10 @@
 // Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
-import { assertEquals, assertRejects, fail } from "./test_util.ts";
+import {
+  assertEquals,
+  assertRejects,
+  assertThrows,
+  fail,
+} from "./test_util.ts";
 
 const {
   core,
@@ -533,3 +538,11 @@ Deno.test(async function decompressionStreamInvalidGzipStillReported() {
     "corrupt gzip stream does not have a matching checksum",
   );
 });
+
+Deno.test(function readableStreamFromWithStringThrows() {
+  assertThrows(
+    () => ReadableStream.from("string"),
+    TypeError,
+    "Failed to execute 'ReadableStream.from': Argument 1 can not be converted to async iterable.",
+  );
+});
diff --git a/tests/unit_node/fetch_test.ts b/tests/unit_node/fetch_test.ts
new file mode 100644
index 00000000000000..cccfded695bb3d
--- /dev/null
+++ b/tests/unit_node/fetch_test.ts
@@ -0,0 +1,18 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+
+import { assertEquals } from "@std/assert/mod.ts";
+import { createReadStream } from "node:fs";
+
+Deno.test("fetch node stream", async () => {
+  const file = createReadStream("tests/testdata/assets/fixture.json");
+
+  const response = await fetch("http://localhost:4545/echo_server", {
+    method: "POST",
+    body: file,
+  });
+
+  assertEquals(
+    response.text(),
+    await Deno.readTextFile("tests/testdata/assets/fixture.json"),
+  );
+});
diff --git a/tests/wpt/runner/expectation.json b/tests/wpt/runner/expectation.json
index cd212f9c4ea64c..8ab6ada6fe913a 100644
--- a/tests/wpt/runner/expectation.json
+++ b/tests/wpt/runner/expectation.json
@@ -4007,8 +4007,14 @@
       "owning-type-message-port.any.worker.html": false,
       "owning-type.any.html": false,
       "owning-type.any.worker.html": false,
-      "from.any.html": true,
-      "from.any.worker.html": true
+      "from.any.html": [
+        "ReadableStream.from ignores a null @@asyncIterator",
+        "ReadableStream.from accepts a string"
+      ],
+      "from.any.worker.html": [
+        "ReadableStream.from ignores a null @@asyncIterator",
+        "ReadableStream.from accepts a string"
+      ]
     },
     "transform-streams": {
       "backpressure.any.html": true,

From a106413cbd66827f942a3747bf5618dd27be5390 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Thu, 18 Jul 2024 16:39:02 +0200
Subject: [PATCH 09/18] update typings

---
 ext/fetch/lib.deno_fetch.d.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ext/fetch/lib.deno_fetch.d.ts b/ext/fetch/lib.deno_fetch.d.ts
index c27313903d4eb5..3bf608cdb439b0 100644
--- a/ext/fetch/lib.deno_fetch.d.ts
+++ b/ext/fetch/lib.deno_fetch.d.ts
@@ -163,6 +163,7 @@ declare type BodyInit =
   | FormData
   | URLSearchParams
   | ReadableStream<Uint8Array>
+  | AsyncIterable<Uint8Array>
   | string;
 /** @category Fetch */
 declare type RequestDestination =

From b3542c416b79732385250534d27868bb8578b894 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Thu, 18 Jul 2024 17:32:27 +0200
Subject: [PATCH 10/18] fix

---
 tests/unit_node/fetch_test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/unit_node/fetch_test.ts b/tests/unit_node/fetch_test.ts
index cccfded695bb3d..e4aca2ce5120ae 100644
--- a/tests/unit_node/fetch_test.ts
+++ b/tests/unit_node/fetch_test.ts
@@ -12,7 +12,7 @@ Deno.test("fetch node stream", async () => {
   });
 
   assertEquals(
-    response.text(),
+    await response.text(),
     await Deno.readTextFile("tests/testdata/assets/fixture.json"),
   );
 });

From 23dc7a55dee7486d7e114f3fe01bb096ff4e8684 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Fri, 19 Jul 2024 01:00:06 +0200
Subject: [PATCH 11/18] fixes

---
 ext/fetch/22_body.js    | 15 ++++++++-------
 ext/webidl/00_webidl.js | 32 ++++++++++++++++++++------------
 2 files changed, 28 insertions(+), 19 deletions(-)

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index 6e0e7276695b1d..28eb6c7ec9d7e0 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -486,13 +486,14 @@ webidl.converters["BodyInit_DOMString"] = (V, prefix, context, opts) => {
     if (ArrayBufferIsView(V)) {
       return webidl.converters["ArrayBufferView"](V, prefix, context, opts);
     }
-
-    return webidl.converters["async iterable<Uint8Array>"](
-      V,
-      prefix,
-      context,
-      opts,
-    );
+    if (webidl.isIterator(V)) {
+      return webidl.converters["async iterable<Uint8Array>"](
+        V,
+        prefix,
+        context,
+        opts,
+      );
+    }
   }
   // BodyInit conversion is passed to extractBody(), which calls core.encode().
   // core.encode() will UTF-8 encode strings with replacement, being equivalent to the USV normalization.
diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index f370a9a99f9ba6..18f1b3438203b9 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -921,6 +921,16 @@ function createSequenceConverter(converter) {
   };
 }
 
+function isIterator(obj) {
+  if (obj[SymbolAsyncIterator] === undefined) {
+    if (obj[SymbolIterator] === undefined) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
 // Ref: https://tc39.es/ecma262/#sec-getiterator
 function getIteratorAsync(obj, prefix, context) {
   const method = obj[SymbolAsyncIterator];
@@ -928,7 +938,7 @@ function getIteratorAsync(obj, prefix, context) {
     const syncMethod = obj[SymbolIterator];
 
     if (syncMethod === undefined) {
-      throw new TypeError("No iterator found");
+      throw new TypeError("No iterator found.");
     }
 
     const iter = FunctionPrototypeCall(syncMethod, obj);
@@ -942,7 +952,14 @@ function getIteratorAsync(obj, prefix, context) {
       );
     }
 
-    return CreateAsyncFromSyncIterator(iter);
+    return {
+      // deno-lint-ignore require-await
+      async next() {
+        // deno-lint-ignore prefer-primordials
+        return iter.next();
+      },
+    };
+    ;
   } else {
     const iter = FunctionPrototypeCall(method, obj);
     if (type(iter) !== "Object") {
@@ -958,16 +975,6 @@ function getIteratorAsync(obj, prefix, context) {
   }
 }
 
-function CreateAsyncFromSyncIterator(iter) {
-  return {
-    // deno-lint-ignore require-await
-    async next() {
-      // deno-lint-ignore prefer-primordials
-      return iter.next();
-    },
-  };
-}
-
 function createAsyncIterableConverter(converter) {
   return function (
     V,
@@ -1420,6 +1427,7 @@ export {
   createSequenceConverter,
   illegalConstructor,
   invokeCallbackFunction,
+  isIterator,
   makeException,
   mixinPairIterable,
   requiredArguments,

From 0265eda0ad99f68df84e2e66ddbca30c99c88330 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Fri, 19 Jul 2024 01:00:26 +0200
Subject: [PATCH 12/18] fmt

---
 ext/webidl/00_webidl.js | 1 -
 1 file changed, 1 deletion(-)

diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index 18f1b3438203b9..398a5a97034ba4 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -959,7 +959,6 @@ function getIteratorAsync(obj, prefix, context) {
         return iter.next();
       },
     };
-    ;
   } else {
     const iter = FunctionPrototypeCall(method, obj);
     if (type(iter) !== "Object") {

From d3a943f703632df649fedcb3479557c5888fd8f5 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Sun, 21 Jul 2024 23:16:15 +0200
Subject: [PATCH 13/18] rework

---
 ext/fetch/22_body.js    |   4 +-
 ext/web/06_streams.js   |   5 +-
 ext/webidl/00_webidl.js | 138 ++++++++++++++++++++--------------------
 3 files changed, 75 insertions(+), 72 deletions(-)

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index 28eb6c7ec9d7e0..a0318d7aad4a36 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -446,8 +446,8 @@ function extractBody(object) {
     if (object.locked || isReadableStreamDisturbed(object)) {
       throw new TypeError("ReadableStream is locked or disturbed");
     }
-  } else if (object[SymbolAsyncIterator] !== undefined) {
-    stream = ReadableStream.from(object);
+  } else if (object[webidl.AsyncIterable] === webidl.AsyncIterable) {
+    stream = ReadableStream.from(object.open());
   }
   if (typeof source === "string") {
     // WARNING: this deviates from spec (expects length to be set)
diff --git a/ext/web/06_streams.js b/ext/web/06_streams.js
index 6b24221a35ba12..ea3a3110f63bba 100644
--- a/ext/web/06_streams.js
+++ b/ext/web/06_streams.js
@@ -5178,10 +5178,11 @@ class ReadableStream {
       prefix,
       "Argument 1",
     );
+    const iter = asyncIterable.open();
 
     const stream = createReadableStream(noop, async () => {
       // deno-lint-ignore prefer-primordials
-      const res = await asyncIterable.next();
+      const res = await iter.next();
       if (res.done) {
         readableStreamDefaultControllerClose(stream[_controller]);
       } else {
@@ -5192,7 +5193,7 @@ class ReadableStream {
       }
     }, async (reason) => {
       // deno-lint-ignore prefer-primordials
-      await asyncIterable.return(reason);
+      await iter.return(reason);
     }, 0);
     return stream;
   }
diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index 398a5a97034ba4..ea7f00002f5b46 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -931,8 +931,7 @@ function isIterator(obj) {
   return true;
 }
 
-// Ref: https://tc39.es/ecma262/#sec-getiterator
-function getIteratorAsync(obj, prefix, context) {
+function getIteratorAsync(obj) {
   const method = obj[SymbolAsyncIterator];
   if (method === undefined) {
     const syncMethod = obj[SymbolIterator];
@@ -941,39 +940,14 @@ function getIteratorAsync(obj, prefix, context) {
       throw new TypeError("No iterator found.");
     }
 
-    const iter = FunctionPrototypeCall(syncMethod, obj);
-
-    if (type(iter) !== "Object") {
-      throw makeException(
-        TypeError,
-        "can not be converted to async iterable.",
-        prefix,
-        context,
-      );
-    }
-
-    return {
-      // deno-lint-ignore require-await
-      async next() {
-        // deno-lint-ignore prefer-primordials
-        return iter.next();
-      },
-    };
+    return [syncMethod, false];
   } else {
-    const iter = FunctionPrototypeCall(method, obj);
-    if (type(iter) !== "Object") {
-      throw makeException(
-        TypeError,
-        "can not be converted to async iterable.",
-        prefix,
-        context,
-      );
-    }
-
-    return iter;
+    return [method, true];
   }
 }
 
+const AsyncIterable = Symbol("[[asyncIterable]]");
+
 function createAsyncIterableConverter(converter) {
   return function (
     V,
@@ -990,56 +964,83 @@ function createAsyncIterableConverter(converter) {
       );
     }
 
-    const iterator = getIteratorAsync(V, prefix, context);
+    const [iterator, isAsync] = getIteratorAsync(V);
 
     return {
-      async next() {
-        // deno-lint-ignore prefer-primordials
-        const iterResult = await iterator.next();
-        if (type(iterResult) !== "Object") {
+      value: V,
+      [AsyncIterable]: AsyncIterable,
+      open() {
+        const iter = FunctionPrototypeCall(iterator, V);
+        if (type(iter) !== "Object") {
           throw makeException(
             TypeError,
-            "can not be converted to async iterable.",
+            "invalid iterator.",
             prefix,
             context,
           );
         }
 
-        if (iterResult.done) {
-          return { done: true };
-        }
-
-        const iterValue = converter(
-          iterResult.value,
-          prefix,
-          context,
-          opts,
-        );
-
-        return { done: false, value: iterValue };
-      },
-      async return(reason) {
-        if (iterator.return === undefined) {
-          return undefined;
-        }
+        let asyncIterator = iter;
 
-        // deno-lint-ignore prefer-primordials
-        const returnPromiseResult = await iterator.return(reason);
-        if (type(returnPromiseResult) !== "Object") {
-          throw makeException(
-            TypeError,
-            "can not be converted to async iterable.",
-            prefix,
-            context,
-          );
+        if (!isAsync) {
+          asyncIterator = {
+            // deno-lint-ignore require-await
+            async next() {
+              // deno-lint-ignore prefer-primordials
+              return iter.next();
+            },
+          };
         }
 
-        return undefined;
-      },
-      [SymbolAsyncIterator]() {
-        return this;
+        return {
+          async next() {
+            // deno-lint-ignore prefer-primordials
+            const iterResult = await asyncIterator.next();
+            if (type(iterResult) !== "Object") {
+              throw makeException(
+                TypeError,
+                "can not be converted to async iterable.",
+                prefix,
+                context,
+              );
+            }
+
+            if (iterResult.done) {
+              return { done: true };
+            }
+
+            const iterValue = converter(
+              iterResult.value,
+              prefix,
+              context,
+              opts,
+            );
+
+            return { done: false, value: iterValue };
+          },
+          async return(reason) {
+            if (asyncIterator.return === undefined) {
+              return undefined;
+            }
+
+            // deno-lint-ignore prefer-primordials
+            const returnPromiseResult = await iterator.return(reason);
+            if (type(returnPromiseResult) !== "Object") {
+              throw makeException(
+                TypeError,
+                "can not be converted to async iterable.",
+                prefix,
+                context,
+              );
+            }
+
+            return undefined;
+          },
+          [SymbolAsyncIterator]() {
+            return this;
+          },
+        };
       },
-      value: V,
     };
   };
 }
@@ -1412,6 +1413,7 @@ function setlike(obj, objPrototype, readonly) {
 
 export {
   assertBranded,
+  AsyncIterable,
   brand,
   configureInterface,
   converters,

From d7c6e32a2ac9ee132b416a655c40fba3c2702488 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Sun, 21 Jul 2024 23:57:54 +0200
Subject: [PATCH 14/18] fix

---
 ext/fetch/22_body.js    |  1 -
 ext/webidl/00_webidl.js | 31 +++++++++++++------------------
 2 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index a0318d7aad4a36..b63d803e6cf7ad 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -32,7 +32,6 @@ const {
   TypedArrayPrototypeSlice,
   TypeError,
   Uint8Array,
-  SymbolAsyncIterator,
 } = primordials;
 
 import * as webidl from "ext:deno_webidl/00_webidl.js";
diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index ea7f00002f5b46..0d878178c07d70 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -931,21 +931,6 @@ function isIterator(obj) {
   return true;
 }
 
-function getIteratorAsync(obj) {
-  const method = obj[SymbolAsyncIterator];
-  if (method === undefined) {
-    const syncMethod = obj[SymbolIterator];
-
-    if (syncMethod === undefined) {
-      throw new TypeError("No iterator found.");
-    }
-
-    return [syncMethod, false];
-  } else {
-    return [method, true];
-  }
-}
-
 const AsyncIterable = Symbol("[[asyncIterable]]");
 
 function createAsyncIterableConverter(converter) {
@@ -964,13 +949,23 @@ function createAsyncIterableConverter(converter) {
       );
     }
 
-    const [iterator, isAsync] = getIteratorAsync(V);
+    let isAsync = true;
+    let method = V[SymbolAsyncIterator];
+    if (method === undefined) {
+      method = V[SymbolIterator];
+
+      if (method === undefined) {
+        throw new TypeError("No iterator found.");
+      }
+
+      isAsync = true;
+    }
 
     return {
       value: V,
       [AsyncIterable]: AsyncIterable,
       open() {
-        const iter = FunctionPrototypeCall(iterator, V);
+        const iter = FunctionPrototypeCall(method, V);
         if (type(iter) !== "Object") {
           throw makeException(
             TypeError,
@@ -1024,7 +1019,7 @@ function createAsyncIterableConverter(converter) {
             }
 
             // deno-lint-ignore prefer-primordials
-            const returnPromiseResult = await iterator.return(reason);
+            const returnPromiseResult = await asyncIterator.return(reason);
             if (type(returnPromiseResult) !== "Object") {
               throw makeException(
                 TypeError,

From f130c1943a154edb8edbe4ca9a01e8e489523184 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Fri, 2 Aug 2024 16:05:33 +0200
Subject: [PATCH 15/18] address comments Co-authored-by: Luca Casonato
 <hello@lcas.dev>

---
 ext/fetch/22_body.js    |  2 +-
 ext/webidl/00_webidl.js | 38 ++++++++++++++------------------------
 2 files changed, 15 insertions(+), 25 deletions(-)

diff --git a/ext/fetch/22_body.js b/ext/fetch/22_body.js
index b63d803e6cf7ad..9a2573fc322c94 100644
--- a/ext/fetch/22_body.js
+++ b/ext/fetch/22_body.js
@@ -485,7 +485,7 @@ webidl.converters["BodyInit_DOMString"] = (V, prefix, context, opts) => {
     if (ArrayBufferIsView(V)) {
       return webidl.converters["ArrayBufferView"](V, prefix, context, opts);
     }
-    if (webidl.isIterator(V)) {
+    if (webidl.isAsyncIterator(V)) {
       return webidl.converters["async iterable<Uint8Array>"](
         V,
         prefix,
diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index 0d878178c07d70..639ad125828a67 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -921,7 +921,7 @@ function createSequenceConverter(converter) {
   };
 }
 
-function isIterator(obj) {
+function isAsyncIterator(obj) {
   if (obj[SymbolAsyncIterator] === undefined) {
     if (obj[SymbolIterator] === undefined) {
       return false;
@@ -955,24 +955,24 @@ function createAsyncIterableConverter(converter) {
       method = V[SymbolIterator];
 
       if (method === undefined) {
-        throw new TypeError("No iterator found.");
+      throw makeException(
+        TypeError,
+        "is not iterable.",
+        prefix,
+        context,
+      );
       }
 
-      isAsync = true;
+      isAsync = false;
     }
 
     return {
       value: V,
       [AsyncIterable]: AsyncIterable,
-      open() {
+      open(context) {
         const iter = FunctionPrototypeCall(method, V);
         if (type(iter) !== "Object") {
-          throw makeException(
-            TypeError,
-            "invalid iterator.",
-            prefix,
-            context,
-          );
+          throw new TypeError(`${context} could not be iterated because iterator method did not return object, but ${type(iter)}.`);
         }
 
         let asyncIterator = iter;
@@ -992,12 +992,7 @@ function createAsyncIterableConverter(converter) {
             // deno-lint-ignore prefer-primordials
             const iterResult = await asyncIterator.next();
             if (type(iterResult) !== "Object") {
-              throw makeException(
-                TypeError,
-                "can not be converted to async iterable.",
-                prefix,
-                context,
-              );
+              throw TypeError(`${context} failed to iterate next value because the next() method did not return an object, but ${type(iterResult)}.`);
             }
 
             if (iterResult.done) {
@@ -1006,8 +1001,8 @@ function createAsyncIterableConverter(converter) {
 
             const iterValue = converter(
               iterResult.value,
-              prefix,
-              context,
+              `${context} failed to iterate next value`,
+              `The value returned from the next() method`,
               opts,
             );
 
@@ -1021,12 +1016,7 @@ function createAsyncIterableConverter(converter) {
             // deno-lint-ignore prefer-primordials
             const returnPromiseResult = await asyncIterator.return(reason);
             if (type(returnPromiseResult) !== "Object") {
-              throw makeException(
-                TypeError,
-                "can not be converted to async iterable.",
-                prefix,
-                context,
-              );
+              throw TypeError(`${context} failed to close iterator because the return() method did not return an object, but ${type(returnPromiseResult)}.`);
             }
 
             return undefined;

From 0e5faf876d317685166e2d2d825b8cb5c2df9300 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Fri, 2 Aug 2024 16:06:19 +0200
Subject: [PATCH 16/18] fmt

---
 ext/webidl/00_webidl.js | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index 639ad125828a67..4b8916f2cf3f93 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -955,12 +955,12 @@ function createAsyncIterableConverter(converter) {
       method = V[SymbolIterator];
 
       if (method === undefined) {
-      throw makeException(
-        TypeError,
-        "is not iterable.",
-        prefix,
-        context,
-      );
+        throw makeException(
+          TypeError,
+          "is not iterable.",
+          prefix,
+          context,
+        );
       }
 
       isAsync = false;
@@ -972,7 +972,11 @@ function createAsyncIterableConverter(converter) {
       open(context) {
         const iter = FunctionPrototypeCall(method, V);
         if (type(iter) !== "Object") {
-          throw new TypeError(`${context} could not be iterated because iterator method did not return object, but ${type(iter)}.`);
+          throw new TypeError(
+            `${context} could not be iterated because iterator method did not return object, but ${
+              type(iter)
+            }.`,
+          );
         }
 
         let asyncIterator = iter;
@@ -992,7 +996,11 @@ function createAsyncIterableConverter(converter) {
             // deno-lint-ignore prefer-primordials
             const iterResult = await asyncIterator.next();
             if (type(iterResult) !== "Object") {
-              throw TypeError(`${context} failed to iterate next value because the next() method did not return an object, but ${type(iterResult)}.`);
+              throw TypeError(
+                `${context} failed to iterate next value because the next() method did not return an object, but ${
+                  type(iterResult)
+                }.`,
+              );
             }
 
             if (iterResult.done) {
@@ -1016,7 +1024,11 @@ function createAsyncIterableConverter(converter) {
             // deno-lint-ignore prefer-primordials
             const returnPromiseResult = await asyncIterator.return(reason);
             if (type(returnPromiseResult) !== "Object") {
-              throw TypeError(`${context} failed to close iterator because the return() method did not return an object, but ${type(returnPromiseResult)}.`);
+              throw TypeError(
+                `${context} failed to close iterator because the return() method did not return an object, but ${
+                  type(returnPromiseResult)
+                }.`,
+              );
             }
 
             return undefined;

From e6176f63c7242b1ae945dcb46006bef9e52649b2 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Fri, 2 Aug 2024 16:40:47 +0200
Subject: [PATCH 17/18] fix

---
 ext/webidl/00_webidl.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index 4b8916f2cf3f93..7440e47e7baf3a 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -1425,7 +1425,7 @@ export {
   createSequenceConverter,
   illegalConstructor,
   invokeCallbackFunction,
-  isIterator,
+  isAsyncIterator,
   makeException,
   mixinPairIterable,
   requiredArguments,

From 81c30e8fc8929580a27b113d76877e00f7638350 Mon Sep 17 00:00:00 2001
From: crowlkats <crowlkats@toaxl.com>
Date: Fri, 2 Aug 2024 20:42:29 +0200
Subject: [PATCH 18/18] fix test

---
 tests/unit_node/fetch_test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/unit_node/fetch_test.ts b/tests/unit_node/fetch_test.ts
index e4aca2ce5120ae..399d6052a56377 100644
--- a/tests/unit_node/fetch_test.ts
+++ b/tests/unit_node/fetch_test.ts
@@ -1,6 +1,6 @@
 // Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
 
-import { assertEquals } from "@std/assert/mod.ts";
+import { assertEquals } from "@std/assert";
 import { createReadStream } from "node:fs";
 
 Deno.test("fetch node stream", async () => {