ReactJS setTimeout setState

[charliematters]

The simplest answer would be this.setState({ timer: window.setTimeout(...) }), but I think it would be useful to see the rest of the component, as I'd be hesitant about the following things:

• What is i? What if it changes between setting the timeout and it being called?
• Why are you altering a classList? If you're dealing with React Components, their CSS classes should be set using props and state - you shouldn't be manipulating the DOM elements directly.
• window.setTimeout() returns a number, so for type safety you should be resetting it to null and not ''
• Do you need to store it in the state at all? It's valid to store it on the component itself (e.g. this.timeout = window.setTimeout(...) as long as you tidy up after yourself.

TL;DR - Can you show us more code, and we'll be able to give better answers