All the code for this project is available on https://github.com/mitjafelicijan/sparklines.
Bar charts are the default charts if no type if provided.
Line charts can have a bunch of data and still be readable.
For better readability, use pie charts only when you have small amount of data points.
Stacked charts can only be horizontal. Rotate with CSS to have them be vertical.
Hover over charts to see details data about that datapoint.
Either click on the button or let timers do it periodically.