refactor handleFieldError

= integrate locatedError, which was always called on the input
= avoid constant return value, which causes return value to hide value of this constant
= add optional asyncPayloadRecord parameter so that caller does not have to supply errors list

Author: yaacovCR

src/execution/execute.ts

@@ -501,7 +501,6 @@ function executeField(
   fieldGroup: FieldGroup,
   path: Path,
 ): PromiseOrValue<unknown> {
-  const errors = exeContext.errors;
   const fieldName = fieldGroup[0].name.value;
   const fieldDef = exeContext.schema.getField(parentType, fieldName);
   if (!fieldDef) {
@@ -561,14 +560,14 @@ function executeField(
       // Note: we don't rely on a `catch` method, but we do expect "thenable"
       // to take a second callback for the error case.
       return completed.then(undefined, (rawError) => {
-        const error = locatedError(rawError, fieldGroup, pathToArray(path));
-        return handleFieldError(error, returnType, errors);
+        handleFieldError(rawError, exeContext, returnType, fieldGroup, path);
+        return null;
       });
     }
     return completed;
   } catch (rawError) {
-    const error = locatedError(rawError, fieldGroup, pathToArray(path));
-    return handleFieldError(error, returnType, errors);
+    handleFieldError(rawError, exeContext, returnType, fieldGroup, path);
+    return null;
   }
 }
 
@@ -600,10 +599,14 @@ export function buildResolveInfo(
 }
 
 function handleFieldError(
-  error: GraphQLError,
+  rawError: unknown,
+  exeContext: ExecutionContext,
   returnType: GraphQLOutputType,
-  errors: Array<GraphQLError>,
-): null {
+  fieldGroup: FieldGroup,
+  path: Path,
+): void {
+  const error = locatedError(rawError, fieldGroup, pathToArray(path));
+
   // If the field type is non-nullable, then it is resolved without any
   // protection from errors, however it still properly locates the error.
   if (isNonNullType(returnType)) {
@@ -612,8 +615,7 @@ function handleFieldError(
 
   // Otherwise, error protection is applied, logging the error and resolving
   // a null value for this field if one is encountered.
-  errors.push(error);
-  return null;
+  exeContext.errors.push(error);
 }
 
 /**
@@ -746,8 +748,8 @@ async function completePromisedValue(
     }
     return completed;
   } catch (rawError) {
-    const error = locatedError(rawError, fieldGroup, pathToArray(path));
-    return handleFieldError(error, returnType, exeContext.errors);
+    handleFieldError(rawError, exeContext, returnType, fieldGroup, path);
+    return null;
   }
 }
 
@@ -763,7 +765,6 @@ async function completeAsyncIteratorValue(
   path: Path,
   iterator: AsyncIterator<unknown>,
 ): Promise<ReadonlyArray<unknown>> {
-  const errors = exeContext.errors;
   let containsPromise = false;
   const completedResults: Array<unknown> = [];
   let index = 0;
@@ -778,16 +779,15 @@ async function completeAsyncIteratorValue(
         break;
       }
     } catch (rawError) {
-      const error = locatedError(rawError, fieldGroup, pathToArray(itemPath));
-      completedResults.push(handleFieldError(error, itemType, errors));
+      handleFieldError(rawError, exeContext, itemType, fieldGroup, itemPath);
+      completedResults.push(null);
       break;
     }
 
     if (
       completeListItemValue(
         iteration.value,
         completedResults,
-        errors,
         exeContext,
         itemType,
         fieldGroup,
@@ -815,7 +815,6 @@ function completeListValue(
   result: unknown,
 ): PromiseOrValue<ReadonlyArray<unknown>> {
   const itemType = returnType.ofType;
-  const errors = exeContext.errors;
 
   if (isAsyncIterable(result)) {
     const iterator = result[Symbol.asyncIterator]();
@@ -850,7 +849,6 @@ function completeListValue(
       completeListItemValue(
         item,
         completedResults,
-        errors,
         exeContext,
         itemType,
         fieldGroup,
@@ -875,7 +873,6 @@ function completeListValue(
 function completeListItemValue(
   item: unknown,
   completedResults: Array<unknown>,
-  errors: Array<GraphQLError>,
   exeContext: ExecutionContext,
   itemType: GraphQLOutputType,
   fieldGroup: FieldGroup,
@@ -912,12 +909,14 @@ function completeListItemValue(
       // to take a second callback for the error case.
       completedResults.push(
         completedItem.then(undefined, (rawError) => {
-          const error = locatedError(
+          handleFieldError(
             rawError,
+            exeContext,
+            itemType,
             fieldGroup,
-            pathToArray(itemPath),
+            itemPath,
           );
-          return handleFieldError(error, itemType, errors);
+          return null;
         }),
       );
 
@@ -926,9 +925,8 @@ function completeListItemValue(
 
     completedResults.push(completedItem);
   } catch (rawError) {
-    const error = locatedError(rawError, fieldGroup, pathToArray(itemPath));
-    const handledError = handleFieldError(error, itemType, errors);
-    completedResults.push(handledError);
+    handleFieldError(rawError, exeContext, itemType, fieldGroup, itemPath);
+    completedResults.push(null);
   }
 
   return false;