diff --git a/src/djb2.js b/src/djb2.js
index 3e417c2..b2728b6 100644
--- a/src/djb2.js
+++ b/src/djb2.js
@@ -1,3 +1,7 @@
+/**
+ * @param {string} toHash
+ * @return {string}
+ */
 export const djb2 = function djb2(toHash) {
   let hash = 5381
   let c
diff --git a/src/sdbm.js b/src/sdbm.js
index ff59e83..9d7dcc3 100644
--- a/src/sdbm.js
+++ b/src/sdbm.js
@@ -1,3 +1,7 @@
+/**
+ * @param {string} toHash
+ * @return {string}
+ */
 export function sdbm(toHash) {
   let hash = BigInt(0)
   let c
@@ -10,6 +14,10 @@ export function sdbm(toHash) {
   return '' + hash
 }
 
+/**
+ * @param {string} toHash
+ * @return {string}
+ */
 export function sdbmGawk(toHash) {
   let hash = BigInt(0)