Decoding CBOR with PureScript

Simon Hafner — Wed, 17 Nov 2021 22:07:38 +0000

If you want to decode cbor data from PureScript, there's cborg, which works just fine... if you use useMaps to deal with the Error: CBOR decode error: non-string keys not supported (got number) errors. Afterwards you have javascript Maps, which can't be decoded with argonaut. I use this code as workaround:

const toObject = function(cbor) {
  if (cbor instanceof Map) {
    var obj = {}
    cbor.forEach(function(value, key) {
      obj[key.toString()] = toObject(value);
    });
    return obj;
  } else {
    if (cbor instanceof Array) {
      return cbor.map(ob => toObject(ob));
    } else {
      if (cbor instanceof Object) {
        var obj = {}
        cbor.forEach(function(value, key) {
          obj[key.toString()] = toObject(value);
        });
        return obj;
      } else {
        return cbor
      }
    }
  }
}

After that, you can decode the tags as string keys, e.g.

decodeJson cbor :: _ { "1" :: Int }

DEV Community: Simon Hafner

Decoding CBOR with PureScript