[Fix] jsx-key: detect conditional returns

Author: yialo

CHANGELOG.md

@@ -10,7 +10,9 @@ This change log adheres to standards from [Keep a CHANGELOG](https://keepachange
 
 ### Fixed
 * [`jsx-no-leaked-render`]: preserve RHS parens for multiline jsx elements while fixing ([#3623][] @akulsr0)
+* [`jsx-key`]: detect conditional returns ([#3630][] @yialo)
 
+[#3630]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3630
 [#3623]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3623
 [#3615]: https://github.com/jsx-eslint/eslint-plugin-react/pull/3615
 

lib/rules/jsx-key.js

@@ -96,6 +96,8 @@ module.exports = {
         if (node.alternate) {
           getReturnStatements(node.alternate, returnStatements);
         }
+      } else if (node.type === 'ReturnStatement') {
+        returnStatements.push(node);
       } else if (Array.isArray(node.body)) {
         node.body.forEach((item) => {
           if (item.type === 'IfStatement') {

tests/lib/rules/jsx-key.js

@@ -387,5 +387,27 @@ ruleTester.run('jsx-key', rule, {
         { messageId: 'missingIterKey' },
       ],
     },
+    {
+      code: `
+        const TestCase = () => {
+          const list = [1, 2, 3, 4, 5];
+
+          return (
+            <div>
+              {list.map(item => {
+                if (item < 2) return <div>{item}</div>;
+                else if (item < 5) return <div />;
+                else return <div />;
+              })}
+            </div>
+          );
+        };
+      `,
+      errors: [
+        { messageId: 'missingIterKey' },
+        { messageId: 'missingIterKey' },
+        { messageId: 'missingIterKey' },
+      ],
+    },
   ]),
 });