ApiAiClient request to Dialogflow API fails in Internet Explorer 11?

Question

I use React and SPFX, when I try to connect to the Dialogflow API it fails in IE. It works in other browsers(Chrome, Edge, Firefox).

import { ApiAiClient } from 'api-ai-javascript';

var accessToken = "...";
var client = new ApiAiClient({accessToken});

'new ApiAiClient()' does not work in IE? Because of this problem my webpart in SharePoint won't load at all.

I'm getting this error in the IE console