diff --git a/shared/js/timers.js b/shared/js/timers.js
index 9efefc78..47be0788 100644
--- a/shared/js/timers.js
+++ b/shared/js/timers.js
@@ -38,6 +38,7 @@ class Timer {
     lastTick;
     /** @type {boolean} */
     once;
+
     /** @type {{ fileName: string, lineNumber: number }} */
     location;
 
@@ -81,6 +82,7 @@ class Timer {
         assertIsType(type, "number", "Expected a number as first argument");
         assertIsType(callback, "function", "Expected a function as second argument");
         assertIsType(interval, "number", "Expected a number as third argument");
+        assertIsType(once, "boolean", "Expected a boolean as fourth argument");
 
         this.interval = interval;
         this.callback = callback.bind(this, ...(Array.isArray(args) ? args : []));
diff --git a/types/shared/index.d.ts b/types/shared/index.d.ts
index cf0b639a..305677c9 100644
--- a/types/shared/index.d.ts
+++ b/types/shared/index.d.ts
@@ -3468,7 +3468,7 @@ declare abstract class Timer {
     public interval: number;
     public callback: Function;
     public lastTick: number;
-    public once?: boolean;
+    public once: boolean;
     public location: import("@altv/shared").SourceLocation;
 
     public get type(): import("@altv/shared").Enums.TimerType;
diff --git a/types/shared/package.json b/types/shared/package.json
index aefe9daa..83a6fa75 100644
--- a/types/shared/package.json
+++ b/types/shared/package.json
@@ -1,6 +1,6 @@
 {
     "name": "@altv/shared",
-    "version": "0.0.23",
+    "version": "0.0.24",
     "description": "This package contains the type definitions for the alt:V JS module v2 shared types",
     "types": "index.d.ts",
     "files": [