If you're looking for a chart library for a web client, I also recommend charts.css. It's a godsend honestly, the concept is way simpler than most charts libraries and can achieve the same thing. Makes it so simple to use the old way, server side rendering, htmx, etc...
In the same vein, I've long had a soft-spot for the JS-enhanced https://pancake-charts.surge.sh/ (developed by NYT graphics team and used for the covid charts).
Did you even look at echarts demos, or amcharts demos for that matter -- it's basically the same thing, but paid for: https://www.amcharts.com/demos ?
I don't have anything against charts.css, but it's like comparing a children's plastic toy to a real space shuttle. I spend most of my work hours developing a heavy business analytics application (not unlike Apache Superset), and it would simply be impossible to implement it with something like chart.css
While I agree with other replies that ECharts provides a lot more functionality than this lib, it does look very nice the way it transforms a semantic table of data into the chart!
I'm using ECharts (and happy with it) but there are some places where I want like a sparkline in every row of a data table, which is a lot of ECharts instances to instantiate, and this lib looks like it'd be great for that.
https://chartscss.org/