Revert "Upgrade React to 16.8.2: Welcome React Hooks (#13992)" (#14017)

This reverts commit 6f88bec.

lib/client-assets.php

@@ -540,12 +540,12 @@ function gutenberg_register_vendor_scripts() {
 
 	gutenberg_register_vendor_script(
 		'react',
-		'https://unpkg.com/react@16.8.2/umd/react' . $react_suffix . '.js',
+		'https://unpkg.com/react@16.6.3/umd/react' . $react_suffix . '.js',
 		array( 'wp-polyfill' )
 	);
 	gutenberg_register_vendor_script(
 		'react-dom',
-		'https://unpkg.com/react-dom@16.8.2/umd/react-dom' . $react_suffix . '.js',
+		'https://unpkg.com/react-dom@16.6.3/umd/react-dom' . $react_suffix . '.js',
 		array( 'react' )
 	);
 	$moment_script = SCRIPT_DEBUG ? 'moment.js' : 'min/moment.min.js';

package.json

@@ -104,8 +104,8 @@
 		"pegjs": "0.10.0",
 		"phpegjs": "1.0.0-beta7",
 		"postcss": "7.0.13",
-		"react-dom": "16.8.2",
-		"react-test-renderer": "16.8.2",
+		"react-dom": "16.6.3",
+		"react-test-renderer": "16.6.3",
 		"redux": "4.0.0",
 		"rimraf": "2.6.2",
 		"rtlcss": "2.4.0",

packages/element/package.json

@@ -24,8 +24,8 @@
 		"@babel/runtime": "^7.3.1",
 		"@wordpress/escape-html": "file:../escape-html",
 		"lodash": "^4.17.11",
-		"react": "^16.8.2",
-		"react-dom": "^16.8.2"
+		"react": "^16.6.3",
+		"react-dom": "^16.6.3"
 	},
 	"publishConfig": {
 		"access": "public"

packages/element/src/react.js

@@ -12,16 +12,6 @@ import {
 	Fragment,
 	isValidElement,
 	StrictMode,
-	useState,
-	useEffect,
-	useContext,
-	useReducer,
-	useCallback,
-	useMemo,
-	useRef,
-	useImperativeHandle,
-	useLayoutEffect,
-	useDebugValue,
 } from 'react';
 import { isString } from 'lodash';
 
@@ -103,22 +93,6 @@ export { isValidElement };
 
 export { StrictMode };
 
-/**
- * Make React Hooks available
- */
-export {
-	useCallback,
-	useContext,
-	useDebugValue,
-	useEffect,
-	useImperativeHandle,
-	useLayoutEffect,
-	useMemo,
-	useReducer,
-	useRef,
-	useState,
-};
-
 /**
  * Concatenate two or more React children objects.
  *