stream: throw TypeError when criteria fulfilled in getIterator

Author: jakecastelli

lib/internal/webstreams/util.js

@@ -18,6 +18,7 @@ const {
 
 const {
   codes: {
+    ERR_ARG_NOT_ITERABLE,
     ERR_INVALID_ARG_VALUE,
     ERR_INVALID_STATE,
     ERR_OPERATION_FAILED,
@@ -235,6 +236,11 @@ function getIterator(obj, kind = 'sync', method) {
       method = obj[SymbolAsyncIterator];
       if (method === undefined) {
         const syncMethod = obj[SymbolIterator];
+
+        if (syncMethod === undefined) {
+          throw new ERR_ARG_NOT_ITERABLE(obj);
+        }
+
         const syncIteratorRecord = getIterator(obj, 'sync', syncMethod);
         return createAsyncFromSyncIterator(syncIteratorRecord);
       }
@@ -243,6 +249,10 @@ function getIterator(obj, kind = 'sync', method) {
     }
   }
 
+  if (method === undefined) {
+    throw new ERR_ARG_NOT_ITERABLE(obj);
+  }
+
   const iterator = FunctionPrototypeCall(method, obj);
   if (typeof iterator !== 'object' || iterator === null) {
     throw new ERR_INVALID_STATE.TypeError('The iterator method must return an object');