stream: simplify readableStreamFromIterable

Signed-off-by: Antoine du Hamel <duhamelantoine1995@gmail.com>
PR-URL: #62651
Reviewed-By: Aviv Keller <me@aviv.sh>

Author: aduh95

lib/internal/webstreams/readablestream.js

@@ -24,6 +24,7 @@ const {
   Symbol,
   SymbolAsyncIterator,
   SymbolDispose,
+  SymbolIterator,
   SymbolToStringTag,
   TypedArrayPrototypeGetLength,
   Uint8Array,
@@ -32,6 +33,7 @@ const {
 const {
   AbortError,
   codes: {
+    ERR_ARG_NOT_ITERABLE,
     ERR_ILLEGAL_CONSTRUCTOR,
     ERR_INVALID_ARG_TYPE,
     ERR_INVALID_ARG_VALUE,
@@ -111,8 +113,6 @@ const {
   nonOpCancel,
   nonOpPull,
   nonOpStart,
-  getIterator,
-  iteratorNext,
   kType,
   kState,
 } = require('internal/webstreams/util');
@@ -1360,41 +1360,36 @@ function createReadableStreamState() {
 
 function readableStreamFromIterable(iterable) {
   let stream;
-  const iteratorRecord = getIterator(iterable, 'async');
-
+  const iteratorGetter = iterable[SymbolAsyncIterator] ?? iterable[SymbolIterator];
+  if (iteratorGetter == null || typeof iteratorGetter !== 'function') {
+    throw new ERR_ARG_NOT_ITERABLE(iterable);
+  }
+  const iterator = FunctionPrototypeCall(iteratorGetter, iterable);
   const startAlgorithm = nonOpStart;
 
   async function pullAlgorithm() {
-    const nextResult = iteratorNext(iteratorRecord);
-    const nextPromise = PromiseResolve(nextResult);
-    return PromisePrototypeThen(nextPromise, (iterResult) => {
-      if (typeof iterResult !== 'object' || iterResult === null) {
-        throw new ERR_INVALID_STATE.TypeError(
-          'The promise returned by the iterator.next() method must fulfill with an object');
-      }
-      if (iterResult.done) {
-        readableStreamDefaultControllerClose(stream[kState].controller);
-      } else {
-        readableStreamDefaultControllerEnqueue(stream[kState].controller, iterResult.value);
-      }
-    });
+    const iterResult = await iterator.next();
+    if (typeof iterResult !== 'object' || iterResult === null) {
+      throw new ERR_INVALID_STATE.TypeError(
+        'The promise returned by the iterator.next() method must fulfill with an object');
+    }
+    if (iterResult.done) {
+      readableStreamDefaultControllerClose(stream[kState].controller);
+    } else {
+      readableStreamDefaultControllerEnqueue(stream[kState].controller, await iterResult.value);
+    }
   }
 
   async function cancelAlgorithm(reason) {
-    const iterator = iteratorRecord.iterator;
     const returnMethod = iterator.return;
     if (returnMethod === undefined) {
-      return PromiseResolve();
+      return;
+    }
+    const iterResult = await FunctionPrototypeCall(returnMethod, iterator, reason);
+    if (typeof iterResult !== 'object' || iterResult === null) {
+      throw new ERR_INVALID_STATE.TypeError(
+        'The promise returned by the iterator.return() method must fulfill with an object');
     }
-    const returnResult = FunctionPrototypeCall(returnMethod, iterator, reason);
-    const returnPromise = PromiseResolve(returnResult);
-    return PromisePrototypeThen(returnPromise, (iterResult) => {
-      if (typeof iterResult !== 'object' || iterResult === null) {
-        throw new ERR_INVALID_STATE.TypeError(
-          'The promise returned by the iterator.return() method must fulfill with an object');
-      }
-      return undefined;
-    });