function loadStylesheet(href) {
  return new Promise(resolve => {
    const link = document.createElement('link');
    link.onload = resolve;
    link.rel = 'stylesheet'
    link.type = 'text/css';
    link.href = href;
    document.head.appendChild(link);
  });
}
function loadStylesheet(href) {
  return new Promise(resolve => {
    const link = document.createElement('link');
    link.onload = resolve;
    link.rel = 'stylesheet'
    link.type = 'text/css';
    link.href = href;
    document.head.appendChild(link);
  });
}
function loadStylesheet ( href ) { return new Promise ( resolve => { const link = document . createElement ( 'link' ) ; link . onload = resolve ; link . rel = 'stylesheet' link . type = 'text/css' ; link . href = href ; document . head . appendChild ( link ) ; } ) ; }
lazy load a stylesheet
lazy load a stylesheet