Decode a xml fetch response with ISO-8859-1 codification to UTF-8

decodeResponse.js

const decodedResponse = await fetch('https://www.anysite.rss.xml', {
    headers: {
      'Content-Type': 'text/xml;charset=ISO-8859-1',
    },
  })
  .then(r => r.arrayBuffer()) // resolve the response stream for buffer
  .then(d => {
    const dataView = new DataView(d); // creates a DataView object representing the buffer data
    const isoDecoder = new TextDecoder('ISO-8859-1'); // creates an instance of the our decoder
    const decodedString = isoDecoder.decode(dataView); // so we pass the stream of bytes for the decoder do its job

    return new window.DOMParser().parseFromString(parsedString, 'text/xml'); // here we transform the string to html
  });