Fetch a stream using JavaScript

We have Linux and an Apache2 web server running. We have an endless ASCII data stream on that server. On one web page, we want to offer that stream contents and some JavaScript to read the data on the client side. We want to open new web browser tabs in reaction to patterns in the stream.

JavaScript's "node-fetch" might be central to this task. A small solution in terms of loaded libraries and installed software is requested, no jQuery/React/... overhead, please.