Initial commit (#12624)

This is the first step - pulling the ReactDOMFrameScheduling module out
into a separate package.

Co-authored-by: Brandon Dail <aweary@users.noreply.github.com>

packages/react-art/src/ReactART.js

@@ -7,7 +7,7 @@
 
 import React from 'react';
 import ReactFiberReconciler from 'react-reconciler';
-import * as ReactDOMFrameScheduling from 'shared/ReactDOMFrameScheduling';
+import * as ReactScheduler from 'react-scheduler';
 import Mode from 'art/modes/current';
 import FastNoSideEffects from 'art/modes/fast-noSideEffects';
 import Transform from 'art/core/transform';
@@ -468,7 +468,7 @@ const ARTRenderer = ReactFiberReconciler({
     return emptyObject;
   },
 
-  scheduleDeferredCallback: ReactDOMFrameScheduling.rIC,
+  scheduleDeferredCallback: ReactScheduler.rIC,
 
   shouldSetTextContent(type, props) {
     return (
@@ -476,7 +476,7 @@ const ARTRenderer = ReactFiberReconciler({
     );
   },
 
-  now: ReactDOMFrameScheduling.now,
+  now: ReactScheduler.now,
 
   mutation: {
     appendChild(parentInstance, child) {

packages/react-dom/src/__tests__/ReactDOM-test.js

@@ -439,4 +439,39 @@ describe('ReactDOM', () => {
       Object.defineProperty(global, 'document', documentDescriptor);
     }
   });
+
+  it('warns when requestAnimationFrame is not polyfilled in the browser', () => {
+    const previousRAF = global.requestAnimationFrame;
+    try {
+      global.requestAnimationFrame = undefined;
+      jest.resetModules();
+      expect(() => require('react-dom')).toWarnDev(
+        'React depends on requestAnimationFrame.',
+      );
+    } finally {
+      global.requestAnimationFrame = previousRAF;
+    }
+  });
+
+  // We're just testing importing, not using it.
+  // It is important because even isomorphic components may import it.
+  it('can import findDOMNode in Node environment', () => {
+    const previousRAF = global.requestAnimationFrame;
+    const previousRIC = global.requestIdleCallback;
+    const prevWindow = global.window;
+    try {
+      global.requestAnimationFrame = undefined;
+      global.requestIdleCallback = undefined;
+      // Simulate the Node environment:
+      delete global.window;
+      jest.resetModules();
+      expect(() => {
+        require('react-dom');
+      }).not.toThrow();
+    } finally {
+      global.requestAnimationFrame = previousRAF;
+      global.requestIdleCallback = previousRIC;
+      global.window = prevWindow;
+    }
+  });
 });

packages/react-dom/src/client/ReactDOM.js

@@ -29,7 +29,7 @@ import * as EventPluginRegistry from 'events/EventPluginRegistry';
 import * as EventPropagators from 'events/EventPropagators';
 import * as ReactInstanceMap from 'shared/ReactInstanceMap';
 import ReactVersion from 'shared/ReactVersion';
-import * as ReactDOMFrameScheduling from 'shared/ReactDOMFrameScheduling';
+import * as ReactScheduler from 'react-scheduler';
 import {ReactCurrentOwner} from 'shared/ReactGlobalSharedState';
 import getComponentName from 'shared/getComponentName';
 import invariant from 'fbjs/lib/invariant';
@@ -688,7 +688,7 @@ const DOMRenderer = ReactFiberReconciler({
     return textNode;
   },
 
-  now: ReactDOMFrameScheduling.now,
+  now: ReactScheduler.now,
 
   mutation: {
     commitMount(
@@ -984,8 +984,8 @@ const DOMRenderer = ReactFiberReconciler({
     },
   },
 
-  scheduleDeferredCallback: ReactDOMFrameScheduling.rIC,
-  cancelDeferredCallback: ReactDOMFrameScheduling.cIC,
+  scheduleDeferredCallback: ReactScheduler.rIC,
+  cancelDeferredCallback: ReactScheduler.cIC,
 });
 
 ReactGenericBatching.injection.injectRenderer(DOMRenderer);

packages/react-scheduler/README.md

@@ -0,0 +1,4 @@
+# React Scheduler
+
+This is a work in progress - we are building a utility to better coordinate
+React and other JavaScript work.

packages/react-scheduler/index.js

@@ -0,0 +1,12 @@
+/**
+ * Copyright (c) 2013-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+'use strict';
+
+export * from './src/ReactScheduler';

packages/react-scheduler/npm/index.js

@@ -0,0 +1,7 @@
+'use strict';
+
+if (process.env.NODE_ENV === 'production') {
+  module.exports = require('./cjs/react-scheduler.production.min.js');
+} else {
+  module.exports = require('./cjs/react-scheduler.development.js');
+}

packages/react-scheduler/package.json

@@ -0,0 +1,23 @@
+{
+  "name": "react-scheduler",
+  "version": "0.1.0-alpha-1",
+  "private": true,
+  "description": "unstable scheduling helper for coordinating React and other JS libraries",
+  "main": "index.js",
+  "repository": "facebook/react",
+  "license": "MIT",
+  "keywords": [
+    "react"
+  ],
+  "bugs": {
+    "url": "https://github.com/facebook/react/issues"
+  },
+  "homepage": "https://reactjs.org/",
+  "files": [
+    "LICENSE",
+    "README.md",
+    "index.js",
+    "cjs/",
+    "umd/"
+  ]
+}

packages/react-scheduler/src/ReactScheduler.js

@@ -7,6 +7,21 @@
  * @flow
  */
 
+'use strict';
+
+/**
+ * A scheduling library to allow scheduling work with more granular priority and
+ * control than requestAnimationFrame and requestIdleCallback.
+ * Current TODO items:
+ * X- Pull out the rIC polyfill built into React
+ * - Initial test coverage
+ * - Support for multiple callbacks
+ * - Support for two priorities; serial and deferred
+ * - Better test coverage
+ * - Better docblock
+ * - Polish documentation, API
+ */
+
 // This is a built-in polyfill for requestIdleCallback. It works by scheduling
 // a requestAnimationFrame, storing the time for the start of the frame, then
 // scheduling a postMessage which gets scheduled after paint. Within the

scripts/rollup/bundles.js

@@ -351,6 +351,16 @@ const bundles = [
     global: 'createSubscription',
     externals: ['react'],
   },
+
+  /******* React Scheduler (experimental) *******/
+  {
+    label: 'react-scheduler',
+    bundleTypes: [NODE_DEV, NODE_PROD, UMD_DEV, UMD_PROD],
+    moduleType: ISOMORPHIC,
+    entry: 'react-scheduler',
+    global: 'ReactScheduler',
+    externals: [],
+  },
 ];
 
 // Based on deep-freeze by substack (public domain)