Convert observables to signals.

frontend/src/app/components/side-menu/side-menu.component.html

@@ -1,4 +1,4 @@
-<div class="menu {{ isOpenned ? 'displayed' : '' }}">
+<div class="menu {{ isOpened ? 'displayed' : '' }}">
     <h1>
         <a [routerLink]="['/home']">
             <img src="assets/images/codiki.png" alt="logo"/>
@@ -16,4 +16,4 @@
     <h2 i18n>Categories</h2>
     <app-categories-menu (categoryClicked)="close()"></app-categories-menu>
 </div>
-<div class="overlay {{ isOpenned ? 'displayed' : ''}}" (click)="close()"></div>
+<div class="overlay {{ isOpened ? 'displayed' : ''}}" (click)="close()"></div>

frontend/src/app/components/side-menu/side-menu.component.ts

@@ -1,4 +1,4 @@
-import { Component } from '@angular/core';
+import {Component, signal} from '@angular/core';
 import { MatIconModule } from '@angular/material/icon';
 import { MatTooltipModule } from '@angular/material/tooltip';
 import { RouterModule } from '@angular/router';
@@ -18,13 +18,13 @@ import { MatRippleModule } from '@angular/material/core';
     ]
 })
 export class SideMenuComponent {
-  isOpenned: boolean = false;
+  isOpened = signal(false);
 
   open(): void {
-    this.isOpenned = true;
+    this.isOpened.set(true);
   }
 
   close(): void {
-    this.isOpenned = false;
+    this.isOpened.set(false);
   }
 }