Tips to optimise rendering of a set of elements in React

There is a guide to increase React performance. The advanced tip will increase speed by 20 times. Rendering a list of some elements in a page is a common task for almost any web-app. In this post I would like to show how to improve performance for that case. For a test example we will create app that draws a set of targets (circles) on the <canvas> element. I will use Redux for a data storage. But