[TASK] add filter and change aria-pressed style button

frontend/main.ts

@@ -33,6 +33,30 @@ function initToggle() {
       });
     });
   }
+
+  const monthToggle = <HTMLInputElement>document.querySelector('#filtermonth-js');
+  const months = ['01', '02', '03', '04', '05', '06', '07', '08', '09', '10', '11', '12'];
+
+  if(monthToggle) {
+    monthToggle.addEventListener('click', () => {
+      monthToggle.ariaPressed = (monthToggle.ariaPressed === 'true') ? 'false' : 'true';
+      const currentMonth = monthToggle.dataset.month;
+      
+      if(currentMonth) {
+        const index = months.indexOf(currentMonth);
+        if (index > -1) { // only splice array when item is found
+          months.splice(index, 1); // 2nd parameter means remove one item only
+        }
+
+        Array.prototype.forEach.call(months, (month: HTMLElement) => {
+          const notThisMonth = document.querySelectorAll('div[data-month="' + month + '"]');
+          Array.prototype.forEach.call(notThisMonth, (notThisMonth: HTMLElement) => {
+            notThisMonth.classList.toggle('hidden');
+          });
+        });
+      }
+    });
+  }
 }
 
 function initSearch() {

frontend/scss/components/_btns.scss

@@ -22,6 +22,6 @@
   }
 
   &[aria-pressed='true'] {
-    @apply outline outline-2 outline-offset-2 outline-primary-600;
+    @apply outline outline-2 outline-offset-2 outline-primary-600 bg-primary-100 text-primary-950;
   }
 }