[Fix] no-namespace: fix crash on non-string React.createElement name

Fixes #3082

Author: ljharb

CHANGELOG.md

@@ -5,6 +5,11 @@ This change log adheres to standards from [Keep a CHANGELOG](http://keepachangel
 
 ## Unreleased
 
+### Fixed
+* [`no-namespace`]: fix crash on non-string React.createElement name ([#3082] @ljharb)
+
+[#3082]: https://github.com/yannickcr/eslint-plugin-react/pull/3082
+
 ## [7.26.0] - 2021.09.20
 
 ### Added

lib/rules/no-namespace.js

@@ -40,7 +40,7 @@ module.exports = {
       CallExpression(node) {
         if (isCreateElement(node, context) && node.arguments.length > 0 && node.arguments[0].type === 'Literal') {
           const name = node.arguments[0].value;
-          if (name.indexOf(':') === -1) return undefined;
+          if (!name || name.indexOf(':') === -1) return undefined;
           report(context, messages.noNamespace, 'noNamespace', {
             node,
             data: {
@@ -51,7 +51,7 @@ module.exports = {
       },
       JSXOpeningElement(node) {
         const name = elementType(node);
-        if (name.indexOf(':') === -1) return undefined;
+        if (!name || name.indexOf(':') === -1) return undefined;
         report(context, messages.noNamespace, 'noNamespace', {
           node,
           data: {

tests/lib/rules/no-namespace.js

@@ -74,6 +74,8 @@ ruleTester.run('no-namespace', rule, {
     code: '<Object.TestComponent />'
   }, {
     code: 'React.createElement("Object.TestComponent")'
+  }, {
+    code: 'React.createElement(null)'
   }],
 
   invalid: [{