diff --git a/types/index.d.ts b/types/index.d.ts
index 1ac6c8dac..28ddcd511 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -382,7 +382,7 @@ declare namespace dayjs {
      *
      * Docs: https://day.js.org/docs/en/query/is-before
      */
-    isBefore(date: ConfigType, unit?: OpUnitType): boolean
+    isBefore(date?: ConfigType, unit?: OpUnitType): boolean
     /**
      * This indicates whether the Day.js object is the same as the other supplied date-time.
      * ```
@@ -408,7 +408,7 @@ declare namespace dayjs {
      *
      * Docs: https://day.js.org/docs/en/query/is-after
      */
-    isAfter(date: ConfigType, unit?: OpUnitType): boolean
+    isAfter(date?: ConfigType, unit?: OpUnitType): boolean
 
     locale(): string