Why Is React App So Slow

This delay is caused by having the inputValue state at the same level as the Menu component. The Menu component contains a list of 807 pokemon, all of which are re-rendering when inputValue changes. This is the nature of React, where all children components are re-rendered based on state or prop changes.

Is React slower than JS?

Vanilla JS initially renders the UI anywhere from 5-10x faster than Preact, and about 30x faster than React! Handling UI state changes with vanilla JS is also orders of magnitude faster than using Preact or React.

Is JavaScript faster than React?

React isn’t “faster than JavaScript“. React is approximately as fast as JavaScript and it’s much harder for you as a developer to muck that up. React is fast by default and it’s slim API is set up in such a way that not knowing how to maintain a solid performance baseline is bordering on egregious oversight.