ts: Convert ui_util module to TypeScript.

static/js/ui_util.ts

@@ -0,0 +1,50 @@
+import $ from "jquery";
+
+// Add functions to this that have no non-trivial
+// dependencies other than jQuery.
+
+export function change_tab_to(tabname: string): void {
+    $(`#gear-menu a[href="${CSS.escape(tabname)}"]`).tab("show");
+}
+
+// https://stackoverflow.com/questions/4233265/contenteditable-set-caret-at-the-end-of-the-text-cross-browser
+export function place_caret_at_end(el: HTMLElement): void {
+    el.focus();
+
+    const range = document.createRange();
+    range.selectNodeContents(el);
+    range.collapse(false);
+    const sel = window.getSelection();
+    sel?.removeAllRanges();
+    sel?.addRange(range);
+}
+
+export function blur_active_element(): void {
+    // this blurs anything that may perhaps be actively focused on.
+    if (document.activeElement instanceof HTMLElement) {
+        document.activeElement.blur();
+    }
+}
+
+export function convert_enter_to_click(e: JQuery.KeyDownEvent): void {
+    if (e.key === "Enter") {
+        e.preventDefault();
+        e.stopPropagation();
+        $(e.currentTarget).trigger("click");
+    }
+}
+
+export function update_unread_count_in_dom(unread_count_elem: JQuery, count: number): void {
+    // This function is used to update unread count in top left corner
+    // elements.
+    const unread_count_span = unread_count_elem.find(".unread_count");
+
+    if (count === 0) {
+        unread_count_span.hide();
+        unread_count_span.text("");
+        return;
+    }
+
+    unread_count_span.show();
+    unread_count_span.text(count);
+}