[TASK] implement search on user interface

frontend/main.ts

@@ -1 +1,33 @@
 import './scss/app.scss'
+
+document.addEventListener('DOMContentLoaded', function() {
+  console.log("init");
+  initSearch();
+});
+
+ function initSearch() {
+  const input = <HTMLInputElement>document.querySelector('#filter-js');
+
+  if(input) {
+    input.addEventListener('input', () => {
+      filterElements(input.value);
+    });
+  }
+}
+
+function filterElements(input: string) {
+  const elements = document.querySelectorAll('form[data-filterable="true"]');
+
+  Array.prototype.forEach.call(elements, (element: HTMLElement) => {
+    // set both strings (input & dataset filter) to lowercase to not be case sensitive
+    let filterString = element.dataset.filter?.toLocaleLowerCase();
+
+    // bulk show all elements
+    element.style.display = 'flex';
+
+    // hide if case doesn't match
+    if(!filterString?.includes(input.toLocaleLowerCase())) {
+      element.style.display = 'none';
+    }
+  });
+}