more DRY less then

Author: yaacovCR

src/execution/subscribe.ts

@@ -8,7 +8,7 @@ import type { PromiseOrValue } from '../jsutils/PromiseOrValue';
 import { GraphQLError } from '../error/GraphQLError';
 import { locatedError } from '../error/locatedError';
 
-import type { DocumentNode } from '../language/ast';
+import type { DocumentNode, FieldNode } from '../language/ast';
 
 import type { GraphQLFieldResolver } from '../type/definition';
 import type { GraphQLSchema } from '../type/schema';
@@ -196,26 +196,15 @@ export function createSourceEventStream(
     const eventStream = executeSubscription(exeContext);
 
     if (isPromise(eventStream)) {
-      return eventStream
-        .then((resolvedEventStream) => ensureAsyncIterable(resolvedEventStream))
-        .then(undefined, (error) => {
-          // If it GraphQLError, report it as an ExecutionResult, containing only errors and no data.
-          // Otherwise treat the error as a system-class error and re-throw it.
-          if (error instanceof GraphQLError) {
-            return { errors: [error] };
-          }
-          throw error;
-        });
+      return eventStream.then(
+        (resolvedEventStream) => ensureAsyncIterable(resolvedEventStream),
+        (error) => handleRawError(error),
+      );
     }
 
     return ensureAsyncIterable(eventStream);
   } catch (error) {
-    // If it GraphQLError, report it as an ExecutionResult, containing only errors and no data.
-    // Otherwise treat the error as a system-class error and re-throw it.
-    if (error instanceof GraphQLError) {
-      return { errors: [error] };
-    }
-    throw error;
+    return handleRawError(error);
   }
 }
 
@@ -231,6 +220,15 @@ function ensureAsyncIterable(eventStream: unknown): AsyncIterable<unknown> {
   return eventStream;
 }
 
+function handleRawError(error: unknown): ExecutionResult {
+  // If it GraphQLError, report it as an ExecutionResult, containing only errors and no data.
+  // Otherwise treat the error as a system-class error and re-throw it.
+  if (error instanceof GraphQLError) {
+    return { errors: [error] };
+  }
+  throw error;
+}
+
 function executeSubscription(exeContext: ExecutionContext): unknown {
   const { schema, fragments, operation, variableValues, rootValue } =
     exeContext;
@@ -290,22 +288,32 @@ function executeSubscription(exeContext: ExecutionContext): unknown {
     const eventStream = resolveFn(rootValue, args, contextValue, info);
 
     if (isPromise(eventStream)) {
-      return eventStream
-        .then((resolvedEventStream) => throwReturnedError(resolvedEventStream))
-        .then(undefined, (error) => {
+      return eventStream.then(
+        (resolvedEventStream) =>
+          throwReturnedError(
+            resolvedEventStream,
+            fieldNodes,
+            pathToArray(path),
+          ),
+        (error) => {
           throw locatedError(error, fieldNodes, pathToArray(path));
-        });
+        },
+      );
     }
 
-    return throwReturnedError(eventStream);
+    return throwReturnedError(eventStream, fieldNodes, pathToArray(path));
   } catch (error) {
     throw locatedError(error, fieldNodes, pathToArray(path));
   }
 }
 
-function throwReturnedError(eventStream: unknown): unknown {
+function throwReturnedError(
+  eventStream: unknown,
+  fieldNodes: ReadonlyArray<FieldNode>,
+  path: ReadonlyArray<string | number>,
+): unknown {
   if (eventStream instanceof Error) {
-    throw eventStream;
+    throw locatedError(eventStream, fieldNodes, path);
   }
   return eventStream;
 }