downloadFlat.js

const svg = document.querySelector("#detail > div > div > div > div > div > div > svg");
const svg2 = document.querySelector("#detail > div > div > section > div > div > div > div > div > img");


const getOuterHTML = () => {
  const html = svg !== null ? svg : svg2
  return html
}

const downloadSvg = () => {
  const svgData = getOuterHTML();
  const svgBlob = new Blob([svgData.outerHTML], {type:"image/svg+xml;charset=utf-8"});
  const svgUrl = URL.createObjectURL(svgBlob);
  const downloadLink = document.createElement("a");
  downloadLink.href = svgUrl
  downloadLink.download = "image.svg"
  document.body.appendChild(downloadLink);
  downloadLink.click()
  document.body.removeChild(downloadLink);
}

downloadSvg();