GET /browser-sync/socket.io/?EIO=3&transport=polling&t=1508510458699-7047 404 0.195 ms - 162

[tjclifford]

I'm getting the error:
/browser-sync/socket.io/?EIO=3&transport=polling&t=1508510458699-7047 404 0.195 ms - 162
....in my console when running the server portion of myRESTApp.
The errors repeat, with an interval of about 5 seconds.
This has not happened before today, and I don't think I've changed anything that would cause the
error, unless I may have upgraded express for another application to v4.15.5.
I've googled the error, and some of them advocate using socket.io in the app:

var io = require('socket.io').listen(server);

var socket = io.connect('http://localhost:3000');

....but doing that has no effect - it also says:

C:\dl\coding\javascript\node.js\0projects\0experiments
var socket = io.connect('http://localhost:3000');
^
TypeError: io.connect is not a function

Thanks for any assistance.