Support hasNext on payloads

Author: robrichard

packages/relay-runtime/network/RelayNetworkTypes.js

@@ -51,6 +51,7 @@ export type GraphQLResponseWithData = {|
   +extensions?: PayloadExtensions,
   +label?: string,
   +path?: Array<string | number>,
+  +hasNext?: boolean,
 |};
 
 export type GraphQLResponseWithoutData = {|
@@ -59,6 +60,7 @@ export type GraphQLResponseWithoutData = {|
   +extensions?: PayloadExtensions,
   +label?: string,
   +path?: Array<string | number>,
+  +hasNext?: boolean,
 |};
 
 export type GraphQLResponseWithExtensionsOnly = {|
@@ -72,6 +74,7 @@ export type GraphQLResponseWithExtensionsOnly = {|
   // does not necessarily indicate that there was an error.
   +data: null,
   +extensions: PayloadExtensions,
+  +hasNext?: boolean,
 |};
 
 export type GraphQLSingularResponse =

packages/relay-runtime/query/__tests__/fetchQueryInternal-test.js

@@ -964,6 +964,30 @@ describe('getObservableForActiveRequest', () => {
     expect(events).toEqual(['next']);
   });
 
+  it('calls next asynchronously with subsequent non-final payloads (OSS)', () => {
+    fetchQuery(environment, query).subscribe({});
+    const observable = getObservableForActiveRequest(
+      environment,
+      query.request,
+    );
+    expect(observable).not.toEqual(null);
+    if (!observable) {
+      return;
+    }
+
+    response = {
+      ...response,
+      extensions: {},
+      hasNext: true,
+    };
+
+    observable.subscribe(observer);
+    expect(events).toEqual([]);
+
+    environment.mock.nextValue(gqlQuery, response);
+    expect(events).toEqual(['next']);
+  });
+
   it('calls complete asynchronously with subsequent final payload', () => {
     fetchQuery(environment, query).subscribe({});
     const observable = getObservableForActiveRequest(
@@ -982,6 +1006,30 @@ describe('getObservableForActiveRequest', () => {
     expect(events).toEqual(['complete']);
   });
 
+  it('calls complete asynchronously with subsequent final payload (OSS)', () => {
+    fetchQuery(environment, query).subscribe({});
+    const observable = getObservableForActiveRequest(
+      environment,
+      query.request,
+    );
+    expect(observable).not.toEqual(null);
+    if (!observable) {
+      return;
+    }
+
+    response = {
+      ...response,
+      extensions: {},
+      hasNext: false,
+    };
+
+    observable.subscribe(observer);
+    expect(events).toEqual([]);
+
+    environment.mock.nextValue(gqlQuery, response);
+    expect(events).toEqual(['complete']);
+  });
+
   describe('when loading @module', () => {
     let operationLoader;
     let resolveModule;

packages/relay-runtime/store/RelayModernQueryExecutor.js

@@ -400,7 +400,7 @@ class Executor {
     if (responsesWithData.length === 0) {
       // no results with data, nothing to process
       // this can occur with extensions-only payloads
-      const isFinal = responses.some(x => x.extensions?.is_final === true);
+      const isFinal = responses.some(x => responseIsFinal(x));
       if (isFinal) {
         this._state = 'loading_final';
         this._updateActiveState();
@@ -1019,7 +1019,7 @@ class Executor {
         incrementalPlaceholders: null,
         moduleImportPayloads: null,
         source: RelayRecordSource.create(),
-        isFinal: response.extensions?.is_final === true,
+        isFinal: responseIsFinal(response),
       };
       this._publishQueue.commitPayload(
         this._operation,
@@ -1296,7 +1296,7 @@ function normalizeResponse(
   return {
     ...relayPayload,
     errors,
-    isFinal: response.extensions?.is_final === true,
+    isFinal: responseIsFinal(response),
   };
 }
 
@@ -1318,4 +1318,17 @@ function validateOptimisticResponsePayload(
   }
 }
 
+/**
+ * Check for both FB specific (extensions?.is_final)
+ * and spec-complaint (hasNext) properties.
+ */
+function responseIsFinal(response: GraphQLSingularResponse): boolean {
+  if (response.extensions?.is_final === true) {
+    return true;
+  } else if (response.hasNext === false) {
+    return true;
+  }
+  return false;
+}
+
 module.exports = {execute};