Nodejs amfjs – Error: No AMF3 type with ID 239

I am making a node app that uses the npm library amfjs to decode a file. I am getting this error: (node:88188) UnhandledPromiseRejectionWarning: Error: No AMF3 type with ID 239

Here’s my code:

async function getDefpack(id) {
  try {
    var url = `https://ajcontent.akamaized.net/${version}/defPacks/${hashIt(id)}`
    var response = await fetch(url).then(response => response.text())
    if (response.includes("Access Denied")) {
      log("That defPack doesn't exist.", "Doesn't Exist.")
    }
    else {
      let rs = new Readable();
      let decoder = new amfjs.AMFDecoder(rs);
      rs.push(new Buffer.from(response)).toString()
      rs.push(null)
      var obj = decoder.decode();
      delete obj.__class;
      if (stringArray.hasOwnProperty(id)) {
        for (var property in obj) {
        var key = stringArray[id];
        if (!stringsJSON.hasOwnProperty(obj[property][key])) continue;
        obj[property].name = stringsJSON[obj[property][key]];
        }
      }
    return JSON.stringify(obj, null, 2);
    }
  }
  catch (err){
    log("nnnn" + err)
  }
}

The error points to my code let decoder = new amfjs.AMFDecoder(rs);, though I am not familiar enough with this library to know what’s going on, so any help would be greatly appreciated!

at Object.fromId (node_modulesamfjslibtypes.js:168:15)
at AMFDecoder.deserialize (node_modulesamfjslibdecoder.js:58:24)
at AMFDecoder.decode (node_modulesamfjslibdecoder.js:53:19)