diff --git a/dist/action.mjs b/dist/action.mjs
index e98a1ee..e3d167c 100644
--- a/dist/action.mjs
+++ b/dist/action.mjs
@@ -82,7 +82,7 @@ async function exec(command, args) {
                 resolve();
             }
             else {
-                reject(new Error(`Command exited with status code ${code}`));
+                reject(new Error(`Command exited with status code ${code.toString()}`));
             }
         });
     });
@@ -136,7 +136,7 @@ function parse(str) {
     const args = [];
     let match;
     while ((match = regex.exec(str)) !== null) {
-        args.push(match[1] ?? match[2] ?? match[3] ?? match[4]);
+        args.push(match[1] || match[2] || match[3] || match[4]);
     }
     return args;
 }
diff --git a/eslint.config.js b/eslint.config.js
index 3ee43ed..b0ec210 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -1,9 +1,20 @@
 import eslint from "@eslint/js";
+import { globalIgnores } from "eslint/config";
 import tseslint from "typescript-eslint";
 
-export default [
+export default tseslint.config(
+  globalIgnores(["dist"]),
   eslint.configs.recommended,
-  ...tseslint.configs.recommended,
-  ...tseslint.configs.stylistic,
-  { ignores: ["dist"] },
-];
+  tseslint.configs.strictTypeChecked,
+  tseslint.configs.stylisticTypeChecked,
+  {
+    languageOptions: {
+      parserOptions: {
+        projectService: {
+          allowDefaultProject: ["eslint.config.js", "rollup.config.js"],
+        },
+        tsconfigRootDir: import.meta.dirname,
+      },
+    },
+  },
+);
diff --git a/src/context.test.ts b/src/context.test.ts
index e351818..385c13c 100644
--- a/src/context.test.ts
+++ b/src/context.test.ts
@@ -183,7 +183,7 @@ describe("get action context", () => {
       const { getInput } = await import("gha-utils");
       const { getContext } = await import("./context.js");
 
-      const inputs = testCase.inputs || {};
+      const inputs = testCase.inputs ?? {};
       vi.mocked(getInput).mockImplementation((name) => inputs[name] ?? "");
 
       expect(getContext()).toStrictEqual({
diff --git a/src/exec.ts b/src/exec.ts
index 2e3e00b..4bb188b 100644
--- a/src/exec.ts
+++ b/src/exec.ts
@@ -17,11 +17,11 @@ export async function exec(command: string, args: string[]): Promise<void> {
     });
     logCommand(proc.spawnfile, ...proc.spawnargs.splice(1));
     proc.on("error", reject);
-    proc.on("close", (code) => {
+    proc.on("close", (code: number) => {
       if (code === 0) {
         resolve();
       } else {
-        reject(new Error(`Command exited with status code ${code}`));
+        reject(new Error(`Command exited with status code ${code.toString()}`));
       }
     });
   });
diff --git a/src/utils.ts b/src/utils.ts
index efa4463..1e6001a 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -12,7 +12,7 @@ export function parse(str: string): string[] {
   const args: string[] = [];
   let match: RegExpExecArray | null;
   while ((match = regex.exec(str)) !== null) {
-    args.push(match[1] ?? match[2] ?? match[3] ?? match[4]);
+    args.push(match[1] || match[2] || match[3] || match[4]);
   }
   return args;
 }