add style to head tag dynamically

ngOnInit() {
  const css = 'a {color: pink;}';
  const head = document.getElementsByTagName('head')[0];
  const style = document.createElement('style');
  style.type = 'text/css';
  style.appendChild(document.createTextNode(css));
  head.appendChild(style);
}

ngOnInit() {
  const css = 'a {color: pink;}';
  const head = document.getElementsByTagName('head')[0];
  const style = document.createElement('style');
  style.type = 'text/css';
  style.appendChild(document.createTextNode(css));
  head.appendChild(style);
}