What is it they do?

Question

JavaScript

How are these animations made? It can't be that each line is written manually, for example, using snap js?
brightmedia.pl

Answer 1

Mostly handles using js, svg, canvas.
But there are software and js libraries that simplify the process.
For example, for svg there is an editor inkscape.paint-net.ru
There are libraries:
https://d3js.org
www.hongkiat.com/blog/javascript-libraries-animate-svg and
others.
plugins for it. There is an article on Habré on the topic:
Greensock: Animation in JavaScript

Answer 2

Pay attention to this pen
codepen.io/nolakat/pen/mWNvdb
in the js settings there are several interesting things)