trilium/apps/client/src/services/focus.ts

let $lastFocusedElement: JQuery<HTMLElement> | null;

// perhaps there should be saved focused element per tab?
export function saveFocusedElement() {
    $lastFocusedElement = $(":focus");
}

export function focusSavedElement() {
    if (!$lastFocusedElement) {
        return;
    }

    if ($lastFocusedElement.hasClass("ck")) {
        // must handle CKEditor separately because of this bug: https://github.com/ckeditor/ckeditor5/issues/607
        // the bug manifests itself in resetting the cursor position to the first character - jumping above

        const editor = $lastFocusedElement.closest(".ck-editor__editable").prop("ckeditorInstance");

        if (editor) {
            editor.editing.view.focus();
        } else {
            console.log("Could not find CKEditor instance to focus last element");
        }
    } else {
        $lastFocusedElement.focus();
    }

    $lastFocusedElement = null;
}