Puck disconnecting after running function from the browser without passing a callback.

Hi Gordon,

I found the issue in the https://www.puck-js.com/puck.js code I believe. I've made some comments below.

    connection.write = function(data, callback) {

// **** This is pushing callback as null ****
      if (data) txDataQueue.push({data:data,callback:callback});
// ***********************

      if (connection.isOpen && !connection.txInProgress) writeChunk();

      function writeChunk() {
        var chunk;
        if (!txDataQueue.length) return;
        var txItem = txDataQueue[0];
        if (txItem.data.length <= CHUNKSIZE) {
          chunk = txItem.data;
          txItem.data = undefined;
        } else {
          chunk = txItem.data.substr(0,CHUNKSIZE);
          txItem.data = txItem.data.substr(CHUNKSIZE);
        }
        connection.txInProgress = true;
        log("BT> Sending "+ JSON.stringify(chunk));
        txCharacteristic.writeValue(str2ab(chunk)).then(function() {
          log("BT> Sent");
          if (!txItem.data) {
            txDataQueue.shift();

// **** This is calling the null callback function and throwing an Error. ****
            txItem.callback();
// ***************************

          }
          connection.txInProgress = false;
          writeChunk();
        }).catch(function(error) {
         log('BT> SEND ERROR: ' + error);
         txDataQueue = [];

// **** The error is being caught and the connection is being closed. ****
         connection.close();
// ********************

        });
      }
    };

Like you said it's an easy fix to only call the callback if one is passed.