Race condition breaking initial Slack badge clicks

[davidalber]

Reproduction:

1. In newly opened browser or incognito window go to https://react-server.io/.
2. Scroll to bottom of page and click the Slack badge.

Bug: the badge does not appear and this is logged to the JavaScript console:

ReferenceError: assignment to undeclared variable unitSize

I am able to get this to reproduce consistently in a new instance of Firefox and only rarely in a Chrome incognito window.

The offending line is in the common.bundle.js file:

If you now reload the page and click the badge the info window will open in the expected way.