nodejs
diff --git a/‎lib/internal/webstreams/readablestream.js‎
Lines changed: 3 additions & 0 deletions b/‎lib/internal/webstreams/readablestream.js‎
Lines changed: 3 additions & 0 deletions
diff --git a/‎test/parallel/test-webstream-readable-from.js‎
Lines changed: 19 additions & 0 deletions b/‎test/parallel/test-webstream-readable-from.js‎
Lines changed: 19 additions & 0 deletions
@@ -1365,6 +1365,9 @@ function readableStreamFromIterable(iterable) {
     throw new ERR_ARG_NOT_ITERABLE(iterable);
   }
   const iterator = FunctionPrototypeCall(iteratorGetter, iterable);
+  if (iterator === null || (typeof iterator !== 'object' && typeof iterator !== 'function')) {
+    throw new ERR_INVALID_STATE.TypeError('The iterator method must return an object');
+  }
   const startAlgorithm = nonOpStart;
 
   async function pullAlgorithm() {
 
@@ -7,3 +7,22 @@ assert.throws(
   () => ReadableStream.from({}),
   { code: 'ERR_ARG_NOT_ITERABLE', name: 'TypeError' },
 );
+
+const invalidIterators = [
+  { [Symbol.iterator]: () => 42 },
+  { [Symbol.asyncIterator]: () => 42 },
+];
+
+for (const iterable of invalidIterators) {
+  assert.throws(
+    () => ReadableStream.from(iterable),
+    { code: 'ERR_INVALID_STATE', name: 'TypeError' },
+  );
+}
+
+function functionIterator() {}
+
+// doesNotThrow
+ReadableStream.from({
+  [Symbol.iterator]: () => functionIterator,
+});
Original file line number	Diff line number	Diff line change
@@ -1365,6 +1365,9 @@ function readableStreamFromIterable(iterable) {
1365	1365	throw new ERR_ARG_NOT_ITERABLE(iterable);
1366	1366	}
1367	1367	const iterator = FunctionPrototypeCall(iteratorGetter, iterable);
	1368	+ if (iterator === null \|\| (typeof iterator !== 'object' && typeof iterator !== 'function')) {
	1369	+ throw new ERR_INVALID_STATE.TypeError('The iterator method must return an object');
	1370	+ }
1368	1371	const startAlgorithm = nonOpStart;
1369	1372
1370	1373	async function pullAlgorithm() {