diff --git a/package.json b/package.json
index 74753bc..b377e66 100644
--- a/package.json
+++ b/package.json
@@ -27,7 +27,7 @@
   "scripts": {
     "build": "rollup --config rollup.config.ts --configPlugin typescript",
     "lint": "eslint .",
-    "test": "npm run lint && npm run coverage",
+    "test": "npm run lint && tsc --noEmit && npm run coverage",
     "open-coverage": "open coverage/lcov-report/index.ts.html",
     "publish-coverage": "npm run coverage && coveralls < coverage/lcov.info",
     "coverage": "vitest run --coverage"
diff --git a/rollup.config.ts b/rollup.config.ts
index b3ef722..bd79c1d 100644
--- a/rollup.config.ts
+++ b/rollup.config.ts
@@ -5,5 +5,5 @@ export default {
   output: {
     file: 'dist/index.mjs',
   },
-  plugins: [typescript()],
+  plugins: [typescript({ include: ['src/index.ts'] })],
 }
diff --git a/src/index.test.ts b/src/index.test.ts
index 295005b..acf7e9d 100644
--- a/src/index.test.ts
+++ b/src/index.test.ts
@@ -1430,4 +1430,19 @@ describe('memoize-fs', () => {
       assert.ok(throws)
     })
   })
+
+  describe('typing', () => {
+    it('should not double-wrap Promise<Promise<T>>', async () => {
+      const cachePath = FIXTURE_CACHE
+      const memoize = memoizeFs({ cachePath })
+
+      const syncFunction: () => number= () => 1;
+      const asyncFunction: () => Promise<number> = async () => 1;
+
+      let memFn: () => Promise<number>;
+      memFn = await memoize.fn(syncFunction);
+      memFn = await memoize.fn(asyncFunction);
+      memFn;
+    })
+  })
 })
diff --git a/tsconfig.json b/tsconfig.json
index e50b4cc..42fa558 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -6,7 +6,8 @@
     "strict": true,
     "moduleResolution": "node",
     "outDir": "dist",
-    "declaration": true
+    "declaration": true,
+    "skipLibCheck": true
   },
-  "include": ["src/index.ts"]
+  "include": ["src"]
 }