React w/SignalR - TypeError: WebSocketClient() not a constructor - node.js

Question

new to React development.
I am building an API client for the BitTrex Exchange API, using their node.js wrapper: node.bittrex.api
With the objective of simply testing the websocket subscription for orderbook updates within the ReactJS framework, here are the steps I have taken:
-Used create-react-app to create the app.
-used npm to install the node.bittrex.api
-added the bittrex client object to the top of the default App.js component and configured options with proper API keys
-added a button (with handler, binded to the button according to React docs) to the default App.js main component,
-inside the handler function, initiated the websocket subscription according to the example code in the node.bittrex.api docs.
The app comes up, but when I press the button, I get an error saying that TypeError Websocketclient() is not a constructor, in the line inside the SignalR.js that creates the websocket connection:
Now I suspect that there is just something specific with the React framework that is screwing this up. Can anyone please help me understand the intricacies? Thanks. Here is my App.js:
import React, { Component } from 'react';
import logo from './logo.svg';
import './App.css';
var bittrex = require('../node_modules/node.bittrex.api/node.bittrex.api.js');
bittrex.options({
'apikey' : process.env.REACT_APP_BTREX_API_KEY,
'apisecret' : process.env.REACT_APP_BTREX_SECRET_KEY,
'verbose' : true,
'cleartext' : false,
'baseUrl' : 'https://bittrex.com/api/v1.1'
});
class App extends Component {
constructor(props) {
super(props);
this.handleClick = this.handleClick.bind(this);
}
handleClick() {
bittrex.websockets.subscribe(['BTC-ETH','BTC-ANS','BTC-GNT'], function(data) {
if (data.M === 'updateExchangeState') {
data.A.forEach(function(data_for) {
console.log('Market Update for '+ data_for.MarketName, data_for);
});
}
});
}
render() {
return (
<div className="App">
<div className="App-header">
<img src={logo} className="App-logo" alt="logo" />
<h2>Welcome to React</h2>
</div>
<br/>
<button onClick={this.handleClick}>Start WS Sub</button>
</div>
);
}
}
export default App;