move handleNext to completeAsyncIterableValue

Author: robrichard

src/execution/execute.js

@@ -919,55 +919,45 @@ function completeValue(
 }
 
 /**
- * Complete a async iterable value by completing each item in the list with
- * the inner type
+ * Complete a async iterator value by completing the result and calling
+ * recursively until all the results are completed.
  */
-function completeAsyncIterableValue(
+function completeAsyncIteratorValue(
   exeContext: ExecutionContext,
-  returnType: GraphQLList<GraphQLOutputType>,
+  itemType: GraphQLOutputType,
   fieldNodes: $ReadOnlyArray<FieldNode>,
   info: GraphQLResolveInfo,
   path: Path,
-  result: AsyncIterable<mixed>,
+  index: number,
+  completedResults: Array<mixed>,
+  iterator: AsyncIterator<mixed>,
 ): Promise<$ReadOnlyArray<mixed>> {
-  // $FlowFixMe
-  const iteratorMethod = result[SYMBOL_ASYNC_ITERATOR];
-  const iterator = iteratorMethod.call(result);
-
-  const completedResults = [];
-  let index = 0;
-
-  const itemType = returnType.ofType;
-
-  function handleNext() {
-    const fieldPath = addPath(path, index);
-    return iterator.next().then(
-      ({ value, done }) => {
-        if (done) {
-          return completedResults;
-        }
-        completedResults.push(
-          completeValue(
-            exeContext,
-            itemType,
-            fieldNodes,
-            info,
-            fieldPath,
-            value,
-          ),
-        );
-        index++;
-        return handleNext();
-      },
-      (error) => {
-        completedResults.push(null);
-        handleFieldError(error, fieldNodes, fieldPath, itemType, exeContext);
+  const fieldPath = addPath(path, index);
+  return iterator.next().then(
+    ({ value, done }) => {
+      if (done) {
         return completedResults;
-      },
-    );
-  }
-
-  return handleNext();
+      }
+      completedResults.push(
+        completeValue(exeContext, itemType, fieldNodes, info, fieldPath, value),
+      );
+      return completeAsyncIteratorValue(
+        exeContext,
+        itemType,
+        fieldNodes,
+        info,
+        path,
+        index + 1,
+        completedResults,
+        iterator,
+      );
+    },
+    (error) => {
+      completedResults.push(null);
+      handleFieldError(error, fieldNodes, fieldPath, itemType, exeContext);
+      return completedResults;
+    },
+  );
 }
 
 /**
@@ -982,14 +972,21 @@ function completeListValue(
   path: Path,
   result: mixed,
 ): PromiseOrValue<$ReadOnlyArray<mixed>> {
+  const itemType = returnType.ofType;
+
   if (isAsyncIterable(result)) {
-    return completeAsyncIterableValue(
+    const iteratorMethod = result[SYMBOL_ASYNC_ITERATOR];
+    const iterator = iteratorMethod.call(result);
+
+    return completeAsyncIteratorValue(
       exeContext,
-      returnType,
+      itemType,
       fieldNodes,
       info,
       path,
-      result,
+      0,
+      [],
+      iterator,
     );
   }
 
@@ -1001,7 +998,6 @@ function completeListValue(
 
   // This is specified as a simple map, however we're optimizing the path
   // where the list contains no Promises by avoiding creating another Promise.
-  const itemType = returnType.ofType;
   let containsPromise = false;
   const completedResults = arrayFrom(result, (item, index) => {
     // No need to modify the info object containing the path,