const idSet = (window as any)._SVG_SPRITE_IDS_ = (window as any)._SVG_SPRITE_IDS_ || [];

const root = document.createElementNS('http://www.w3.org/2000/svg', 'svg') as SVGSVGElement;
root.style.position = 'absolute';
root.style.width = '0';
root.style.height = '0';

function insertRoot() {
  document.body.insertBefore(root, document.body.firstChild);
}

if (document.readyState === 'loading') {
  document.addEventListener('DOMContentLoaded', insertRoot);
} else {
  insertRoot();
}

export default function addSymbol(symbol: string, id: string) {
  if (idSet.indexOf(id) > -1 || document.getElementById(id)) {
    console.warn(`Icon #${id} was duplicately registered. It must be globally unique.`);
  }
  idSet.push(id);

  root.insertAdjacentHTML('beforeend', symbol);
}