https://xkcd.com/1296/

Sentimessenger

Our app lets the user upload their Facebook Messenger data to a familiar looking site. They can download easily from Facebook as a giant HTML file. Then the user can see a colorful visualization of all of their conversations over time with a sentiment analysis.

You can find the source code here: https://github.com/brandondsherman/Sentimessenger

To try it out you have at allow unsafe scripts to be ran in your browser.