diff --git a/optuna_dashboard/package-lock.json b/optuna_dashboard/package-lock.json
index a73210ea..cbaa2760 100644
--- a/optuna_dashboard/package-lock.json
+++ b/optuna_dashboard/package-lock.json
@@ -5460,9 +5460,9 @@
       }
     },
     "node_modules/caniuse-lite": {
-      "version": "1.0.30001608",
-      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001608.tgz",
-      "integrity": "sha512-cjUJTQkk9fQlJR2s4HMuPMvTiRggl0rAVMtthQuyOlDWuqHXqN8azLq+pi8B2TjwKJ32diHjUqRIKeFX4z1FoA==",
+      "version": "1.0.30001609",
+      "resolved": "https://registry.npmjs.org/caniuse-lite/-/caniuse-lite-1.0.30001609.tgz",
+      "integrity": "sha512-JFPQs34lHKx1B5t1EpQpWH4c+29zIyn/haGsbpfq3suuV9v56enjFt23zqijxGTMwy1p/4H2tjnQMY+p1WoAyA==",
       "dev": true,
       "funding": [
         {
diff --git a/tslib/types/src/index.ts b/tslib/types/src/index.ts
index 6fd14375..937abc52 100644
--- a/tslib/types/src/index.ts
+++ b/tslib/types/src/index.ts
@@ -14,7 +14,7 @@ export type IntDistribution = {
   type: "IntDistribution"
   low: number
   high: number
-  step: number | null
+  step: number
   log: boolean
 }