diff --git a/index.d.ts b/index.d.ts
new file mode 100644
index 0000000..27b86d7
--- /dev/null
+++ b/index.d.ts
@@ -0,0 +1,4 @@
+declare module "js-levenshtein" {
+    function levenshtein(a: string, b: string): number;
+    export default levenshtein;
+}
diff --git a/index.js b/index.js
index e3ae013..a0dbcda 100644
--- a/index.js
+++ b/index.js
@@ -12,6 +12,7 @@ module.exports = (function()
             : d1 + 1;
   }
 
+  /** @type {(a: string, b: string) => number} */
   return function(a, b)
   {
     if (a === b) {