Expose lower level async hooks to Relay

This requires an external helper file that we'll wire up internally.

packages/react-flight-dom-relay/src/ReactFlightDOMRelayClient.js

@@ -7,9 +7,7 @@
  * @flow
  */
 
-import type {ReactModelRoot} from 'react-client/src/ReactFlightClient';
-
-import type {Chunk} from './ReactFlightDOMRelayClientHostConfig';
+import type {Response, JSONValue} from 'react-client/src/ReactFlightClient';
 
 import {
   createResponse,
@@ -20,8 +18,6 @@ import {
   close,
 } from 'react-client/src/ReactFlightClient';
 
-type EncodedData = Array<Chunk>;
-
 function parseModel(response, targetObj, key, value) {
   if (typeof value === 'object' && value !== null) {
     if (Array.isArray(value)) {
@@ -42,27 +38,17 @@ function parseModel(response, targetObj, key, value) {
   return parseModelFromJSON(response, targetObj, key, value);
 }
 
-function read<T>(data: EncodedData): ReactModelRoot<T> {
-  let response = createResponse();
-  for (let i = 0; i < data.length; i++) {
-    let chunk = data[i];
-    if (chunk.type === 'json') {
-      resolveModelChunk(
-        response,
-        chunk.id,
-        parseModel(response, {}, '', chunk.json),
-      );
-    } else {
-      resolveErrorChunk(
-        response,
-        chunk.id,
-        chunk.json.message,
-        chunk.json.stack,
-      );
-    }
-  }
-  close(response);
-  return getModelRoot(response);
+export {createResponse, getModelRoot, close};
+
+export function resolveModel(response: Response, id: number, json: JSONValue) {
+  resolveModelChunk(response, id, parseModel(response, {}, '', json));
 }
 
-export {read};
+export function resolveError(
+  response: Response,
+  id: number,
+  message: string,
+  stack: string,
+) {
+  resolveErrorChunk(response, id, message, stack);
+}

packages/react-flight-dom-relay/src/ReactFlightDOMRelayClientHostConfig.js

@@ -7,30 +7,6 @@
  * @flow
  */
 
-type JSONValue =
-  | string
-  | number
-  | boolean
-  | null
-  | {[key: string]: JSONValue}
-  | Array<JSONValue>;
-
-export type Chunk =
-  | {
-      type: 'json',
-      id: number,
-      json: JSONValue,
-    }
-  | {
-      type: 'error',
-      id: number,
-      json: {
-        message: string,
-        stack: string,
-        ...
-      },
-    };
-
 export type StringDecoder = void;
 
 export const supportsBinaryStreams = false;

packages/react-flight-dom-relay/src/ReactFlightDOMRelayServer.js

@@ -8,17 +8,13 @@
  */
 
 import type {ReactModel} from 'react-server/src/ReactFlightServer';
-import type {Chunk} from './ReactFlightDOMRelayServerHostConfig';
+import type {Destination} from './ReactFlightDOMRelayServerHostConfig';
 
 import {createRequest, startWork} from 'react-server/src/ReactFlightServer';
 
-type EncodedData = Array<Chunk>;
-
-function render(model: ReactModel): EncodedData {
-  let data: EncodedData = [];
-  let request = createRequest(model, data);
+function render(model: ReactModel, destination: Destination): void {
+  let request = createRequest(model, destination);
   startWork(request);
-  return data;
 }
 
 export {render};

packages/react-flight-dom-relay/src/ReactFlightDOMRelayServerHostConfig.js

@@ -9,9 +9,13 @@
 
 import type {Request, ReactModel} from 'react-server/src/ReactFlightServer';
 
+import type {Destination} from 'ReactFlightDOMRelayServerIntegration';
+
 import {resolveModelToJSON} from 'react-server/src/ReactFlightServer';
 
-export type Destination = Array<Chunk>;
+import {emitModel, emitError} from 'ReactFlightDOMRelayServerIntegration';
+
+export type {Destination} from 'ReactFlightDOMRelayServerIntegration';
 
 type JSONValue =
   | string
@@ -95,10 +99,14 @@ export function flushBuffered(destination: Destination) {}
 export function beginWriting(destination: Destination) {}
 
 export function writeChunk(destination: Destination, chunk: Chunk): boolean {
-  destination.push(chunk);
+  if (chunk.type === 'json') {
+    emitModel(destination, chunk.id, chunk.json);
+  } else {
+    emitError(destination, chunk.id, chunk.json.message, chunk.json.stack);
+  }
   return true;
 }
 
 export function completeWriting(destination: Destination) {}
 
-export function close(destination: Destination) {}
+export {close} from 'ReactFlightDOMRelayServerIntegration';

packages/react-flight-dom-relay/src/__mocks__/ReactFlightDOMRelayServerIntegration.js

@@ -0,0 +1,28 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+'use strict';
+
+const ReactFlightDOMRelayServerIntegration = {
+  emitModel(destination, id, json) {
+    destination.push({
+      type: 'json',
+      id: id,
+      json: json,
+    });
+  },
+  emitError(destination, id, message, stack) {
+    destination.push({
+      type: 'error',
+      id: id,
+      json: {message, stack},
+    });
+  },
+  close(destination) {},
+};
+
+module.exports = ReactFlightDOMRelayServerIntegration;

packages/react-flight-dom-relay/src/__tests__/ReactFlightDOMRelay-test.internal.js

@@ -7,9 +7,6 @@
 
 'use strict';
 
-// Polyfills for test environment
-global.TextDecoder = require('util').TextDecoder;
-
 let React;
 let ReactDOMFlightRelayServer;
 let ReactDOMFlightRelayClient;
@@ -32,11 +29,30 @@ describe('ReactFlightDOMRelay', () => {
         bar: [<Bar text="a" />, <Bar text="b" />],
       };
     }
-    let data = ReactDOMFlightRelayServer.render({
-      foo: <Foo />,
-    });
-    let root = ReactDOMFlightRelayClient.read(data);
-    let model = root.model;
+    let data = [];
+    ReactDOMFlightRelayServer.render(
+      {
+        foo: <Foo />,
+      },
+      data,
+    );
+
+    let response = ReactDOMFlightRelayClient.createResponse();
+    for (let i = 0; i < data.length; i++) {
+      let chunk = data[i];
+      if (chunk.type === 'json') {
+        ReactDOMFlightRelayClient.resolveModel(response, chunk.id, chunk.json);
+      } else {
+        ReactDOMFlightRelayClient.resolveError(
+          response,
+          chunk.id,
+          chunk.json.message,
+          chunk.json.stack,
+        );
+      }
+    }
+    let model = ReactDOMFlightRelayClient.getModelRoot(response).model;
+    ReactDOMFlightRelayClient.close(response);
     expect(model).toEqual({foo: {bar: ['A', 'B']}});
   });
 });

scripts/flow/config/flowconfig

@@ -29,6 +29,7 @@
 ../environment.js
 ../react-devtools.js
 ../react-native-host-hooks.js
+../react-relay-hooks.js
 
 [lints]
 untyped-type-import=error

scripts/flow/react-relay-hooks.js

@@ -0,0 +1,32 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+type JSONValue =
+  | string
+  | number
+  | boolean
+  | null
+  | {[key: string]: JSONValue}
+  | Array<JSONValue>;
+
+declare module 'ReactFlightDOMRelayServerIntegration' {
+  declare export opaque type Destination;
+  declare export function emitModel(
+    destination: Destination,
+    id: number,
+    json: JSONValue,
+  ): void;
+  declare export function emitError(
+    destination: Destination,
+    id: number,
+    message: string,
+    stack: string,
+  ): void;
+  declare export function close(destination: Destination): void;
+}

scripts/rollup/bundles.js

@@ -203,7 +203,11 @@ const bundles = [
     moduleType: RENDERER,
     entry: 'react-flight-dom-relay/server',
     global: 'ReactFlightDOMRelayServer',
-    externals: ['react', 'react-dom/server'],
+    externals: [
+      'react',
+      'react-dom/server',
+      'ReactFlightDOMRelayServerIntegration',
+    ],
   },
 
   /******* React DOM Flight Client Relay *******/