Replace magic number 1 with ELEMENT_NODE (#13479)

* Replace magic number 1 with ELEMENT_NODE

* Add flow pragma to HTMLNodeType

Author: NE-SmallTown

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

@@ -694,7 +694,7 @@ const ReactDOM: Object = {
 
         // Check if the container itself is a React root node.
         const isContainerReactRoot =
-          container.nodeType === 1 &&
+          container.nodeType === ELEMENT_NODE &&
           isValidContainer(container.parentNode) &&
           !!container.parentNode._reactRootContainer;
 

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

@@ -530,7 +530,7 @@ export function didNotHydrateContainerInstance(
   instance: Instance | TextInstance,
 ) {
   if (__DEV__) {
-    if (instance.nodeType === 1) {
+    if (instance.nodeType === ELEMENT_NODE) {
       warnForDeletedHydratableElement(parentContainer, (instance: any));
     } else {
       warnForDeletedHydratableText(parentContainer, (instance: any));
@@ -545,7 +545,7 @@ export function didNotHydrateInstance(
   instance: Instance | TextInstance,
 ) {
   if (__DEV__ && parentProps[SUPPRESS_HYDRATION_WARNING] !== true) {
-    if (instance.nodeType === 1) {
+    if (instance.nodeType === ELEMENT_NODE) {
       warnForDeletedHydratableElement(parentInstance, (instance: any));
     } else {
       warnForDeletedHydratableText(parentInstance, (instance: any));

packages/react-dom/src/shared/HTMLNodeType.js

@@ -3,6 +3,8 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
  */
 
 /**

packages/react-dom/src/test-utils/ReactTestUtils.js

@@ -20,7 +20,7 @@ import {
 import SyntheticEvent from 'events/SyntheticEvent';
 import invariant from 'shared/invariant';
 import lowPriorityWarning from 'shared/lowPriorityWarning';
-
+import {ELEMENT_NODE} from '../shared/HTMLNodeType';
 import * as DOMTopLevelEventTypes from '../events/DOMTopLevelEventTypes';
 
 const {findDOMNode} = ReactDOM;
@@ -124,7 +124,7 @@ function validateClassInstance(inst, methodName) {
   const stringified = '' + inst;
   if (Array.isArray(inst)) {
     received = 'an array';
-  } else if (inst && inst.nodeType === 1 && inst.tagName) {
+  } else if (inst && inst.nodeType === ELEMENT_NODE && inst.tagName) {
     received = 'a DOM node';
   } else if (stringified === '[object Object]') {
     received = 'object with keys {' + Object.keys(inst).join(', ') + '}';
@@ -169,7 +169,7 @@ const ReactTestUtils = {
   },
 
   isDOMComponent: function(inst) {
-    return !!(inst && inst.nodeType === 1 && inst.tagName);
+    return !!(inst && inst.nodeType === ELEMENT_NODE && inst.tagName);
   },
 
   isDOMComponentElement: function(inst) {