From 28d8cd7a7f54275488e5ad61a5e70bcee6469cf7 Mon Sep 17 00:00:00 2001
From: Olivier Zalmanski <88216225+OlivierZal@users.noreply.github.com>
Date: Tue, 28 Jan 2025 17:04:23 +0100
Subject: [PATCH 1/2] fix(eslint-plugin): [prefer-nullish-coalescing] fix
 missing return

---
 .../src/rules/prefer-nullish-coalescing.ts    |  2 ++
 .../rules/prefer-nullish-coalescing.test.ts   | 24 +++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/packages/eslint-plugin/src/rules/prefer-nullish-coalescing.ts b/packages/eslint-plugin/src/rules/prefer-nullish-coalescing.ts
index bb506b38a6ac..e52f83543af7 100644
--- a/packages/eslint-plugin/src/rules/prefer-nullish-coalescing.ts
+++ b/packages/eslint-plugin/src/rules/prefer-nullish-coalescing.ts
@@ -437,6 +437,8 @@ export default createRule<Options, MessageIds>({
               isNodeEqual(testNode, node.alternate)
             ) {
               identifierOrMemberExpression = testNode;
+            } else {
+              return;
             }
           }
         }
diff --git a/packages/eslint-plugin/tests/rules/prefer-nullish-coalescing.test.ts b/packages/eslint-plugin/tests/rules/prefer-nullish-coalescing.test.ts
index 51442dbc7467..ce4f99237378 100644
--- a/packages/eslint-plugin/tests/rules/prefer-nullish-coalescing.test.ts
+++ b/packages/eslint-plugin/tests/rules/prefer-nullish-coalescing.test.ts
@@ -98,6 +98,30 @@ x ??${equals} 'foo';
       'null != x ? y : x;',
       'undefined != x ? y : x;',
       `
+declare let x: number | undefined;
+x !== 15 && x !== undefined ? x : y;
+      `,
+      `
+declare let x: number | undefined;
+x !== undefined && x !== 15 ? x : y;
+      `,
+      `
+declare let x: number | undefined;
+15 !== x && undefined !== x ? x : y;
+      `,
+      `
+declare let x: number | undefined;
+undefined !== x && 15 !== x ? x : y;
+      `,
+      `
+declare let x: number | undefined;
+15 !== x && x !== undefined ? x : y;
+      `,
+      `
+declare let x: number | undefined;
+undefined !== x && x !== 15 ? x : y;
+      `,
+      `
 declare let x: string;
 x === null ? x : y;
       `,

From 2d267d8830e746fff66fbafaed2644230e7011e2 Mon Sep 17 00:00:00 2001
From: Olivier Zalmanski <88216225+OlivierZal@users.noreply.github.com>
Date: Tue, 28 Jan 2025 18:19:42 +0100
Subject: [PATCH 2/2] add tests

---
 .../tests/rules/prefer-nullish-coalescing.test.ts    | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/packages/eslint-plugin/tests/rules/prefer-nullish-coalescing.test.ts b/packages/eslint-plugin/tests/rules/prefer-nullish-coalescing.test.ts
index ce4f99237378..a9ad05c5cef5 100644
--- a/packages/eslint-plugin/tests/rules/prefer-nullish-coalescing.test.ts
+++ b/packages/eslint-plugin/tests/rules/prefer-nullish-coalescing.test.ts
@@ -122,6 +122,18 @@ declare let x: number | undefined;
 undefined !== x && x !== 15 ? x : y;
       `,
       `
+declare let x: string | undefined;
+x !== 'foo' && x !== undefined ? x : y;
+      `,
+      `
+function test(value: number | undefined): number {
+  return value !== foo() && value !== undefined ? value : 1;
+}
+      `,
+      `
+const test = (value: boolean | undefined): boolean => value !== undefined && value !== false ? value : false;
+      `,
+      `
 declare let x: string;
 x === null ? x : y;
       `,