chpmrc built an extension  to detect these characters, but as some people mentioned, the way the extension worked was less than ideal.
I decided to build a better version that works in the background and alerts the user if they have selected text containing these zero-width characters, showing a notification that allows you to copy a clean version, and a version with zero-width characters replaced by emojis.
I also wrote a blog post about it .
 - https://news.ycombinator.com/item?id=16749422
 - https://news.ycombinator.com/item?id=16754987
 - https://github.com/chpmrc/zero-width-chrome-extension
 - https://medium.com/@aidobreen/hidden-text-fingerprints-and-h...