Dynamically size containers - Angular 6

//Angular 6 -  Dynamically size parent container width
let _container = document.querySelector('.base-component');
if (this.alliances.length > 3) {
    let _pxl = _container['clientWidth'] + (this.alliances.length - 3) * 350;
    _container['style']['width'] = _pxl + 'px';
}