const script = `

onmessage = (evt) => {

  const url = URL.createObjectURL(new Blob([String(evt.data)], {type: 'text/html'}));

  window.parent.postMessage([evt.data, url], '*');

}

`;

const scriptURL = URL.createObjectURL(new Blob([script], {type:'text/javascript'}));

const iframe = Object.assign(document.createElement('iframe'), {

  src: URL.createObjectURL(new Blob([`<script src=${scriptURL}></script>`], {type: 'text/html'}))

});

window.onmessage = (evt) => {

  const [id, src] = evt.data;

  iframe.remove();

  const check = Object.assign(document.createElement('iframe'), {src: src})

  check.onload = () => console.log('loadable after iframe GC');

  check.onerror = () => console.log('error after iframe GC');

  document.body.append(check);

}

iframe.onload = () => {

  iframe.contentWindow.postMessage('post-GC', '*');

}

document.body.append(iframe);