NgBootstrap: Popover Example

Set focus to element in panel directly after it opens

setFilterPanelFocus() {
    setTimeout(function () {
        let filterOptionElems = document.querySelectorAll('#phaListingFilterOptions label.filter-option') as NodeListOf<HTMLElement>;

        if (filterOptionElems && filterOptionElems.length) {
            filterOptionElems[0].focus();
        }
    }, 0);
}

ngAfterViewChecked() {
    if (this.startFilterToggle) {
        this.setFilterPanelFocus();
        this.startFilterToggle = false;
    }
}

filterPanelShown() {
    //this.startFilterToggle = true;
}

filterPanelHidden() {
    //this.startFilterToggle = true;
}