zulip/static/js/ui_util.ts

import $ from "jquery";

import * as keydown_util from "./keydown_util";

// Add functions to this that have no non-trivial
// dependencies other than jQuery.

// 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 (keydown_util.is_enter_event(e)) {
        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);
}

export function update_unread_mention_info_in_dom(
    $unread_mention_info_elem: JQuery,
    stream_has_any_unread_mention_messages: Boolean,
): void {
    const $unread_mention_info_span = $unread_mention_info_elem.find(".unread_mention_info");
    if (!stream_has_any_unread_mention_messages) {
        $unread_mention_info_span.hide();
        $unread_mention_info_span.text("");
        return;
    }

    $unread_mention_info_span.show();
    $unread_mention_info_span.text("@");
}

/**
 * Parse HTML and return a DocumentFragment.
 *
 * Like any consumer of HTML, this function must only be given input
 * from trusted producers of safe HTML, such as auto-escaping
 * templates; violating this expectation will introduce bugs that are
 * likely to be security vulnerabilities.
 */
export function parse_html(html: string): DocumentFragment {
    const template = document.createElement("template");
    template.innerHTML = html;
    return template.content;
}