diff --git a/src/shared/structs/DateOnly.ts b/src/shared/structs/DateOnly.ts
index 690a4b3..e574d23 100644
--- a/src/shared/structs/DateOnly.ts
+++ b/src/shared/structs/DateOnly.ts
@@ -1,42 +1,36 @@
 export class DateOnly {
-  private ticks: number;
-
-  /*
-  constructor(year: number, month: number, day: number) {
-    this.ticks = new Date(year, month - 1, day).getTime();
-  }
-*/
+  private readonly _ticks: number;
 
   constructor(year: number, month: number, day: number);
   constructor(date: Date);
   constructor(date: string);
   constructor(yearOrDate: number | Date | string, month?: number, day?: number) {
     if (yearOrDate instanceof Date) {
-      this.ticks = yearOrDate.getTime();
+      this._ticks = yearOrDate.getTime();
     } else if (typeof yearOrDate === 'number' && month !== undefined && day !== undefined) {
-      this.ticks = new Date(yearOrDate, month - 1, day).getTime();
+      this._ticks = new Date(yearOrDate, month - 1, day).getTime();
     } else if (typeof yearOrDate === 'string') {
       const [year, month, day] = yearOrDate.split('-').map(Number);
-      this.ticks = new Date(year, month - 1, day).getTime();
+      this._ticks = new Date(year, month - 1, day).getTime();
     } else {
       throw new Error('Invalid constructor arguments');
     }
   }
 
   get year(): number {
-    return new Date(this.ticks).getFullYear();
+    return new Date(this._ticks).getFullYear();
   }
 
   get month(): number {
-    return new Date(this.ticks).getMonth() + 1;
+    return new Date(this._ticks).getMonth() + 1;
   }
 
   get day(): number {
-    return new Date(this.ticks).getDate();
+    return new Date(this._ticks).getDate();
   }
 
   get date(): Date {
-    return new Date(this.ticks);
+    return new Date(this._ticks);
   }
 
   toString(): string {