How to visualize the time an employee is online?

Question

Angular

I fix the time at which the employee was online (I record in the database the time of appearance on the network and the time of leaving the network). For example:
from 9:32 to 9:55,
from 11:22 to 14:00
, etc.
I would like to visualize when the employee was online - so that all time intervals are displayed in some kind of chart or graph, or timeline. I'm attaching an example of what I'm showing. In the figure, the working day is from 9:00 to 18:00, in the form of a time line. It displays the intervals when a particular employee was online.
Does anyone have any recommendations on how to google it, ready-made solutions, or maybe similar options? Preliminarily, I am using angular.js with 'ng2-charts'. The usual chart probably won't work, because there are too many intermediate points between two time periods...