Home page examples hooks and classes

[Zeko369]

Upgrade Flow version and add a tab switcher to switch between hooks and class examples on homepage

Closes: #2833

[facebook-github-bot]

Hi @Zeko369!

Thank you for your pull request and welcome to our community.We require contributors to sign our Contributor License Agreement, and we don't seem to have you on file.

In order for us to review and merge your code, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

If you have received this in error or have any questions, please contact us at cla@fb.com. Thanks!

[reactjs-bot]

Deploy preview for reactjs ready!

Built with commit 78605e9

https://deploy-preview-2838--reactjs.netlify.com

[facebook-github-bot]

Thank you for signing our Contributor License Agreement. We can now accept your code for this (and any) Facebook open source project. Thanks!

[Zeko369]

The second example (setInterval) requires the use of useEffect, so I'd rather add a simple counter example (+, - buttons and a value) for the stateful example, add use this for "lifecycle" example.

Any ideas/comments?

[slk333]

a welcomed change that will probably require the approval of managers because it involves the frontpage of the website. Thank you for this pull request and i hope it will bring things forward!

[imedadel]

@gaearon Are you rewriting all the examples using hooks and functional components?

I'd like to help if that's the case :) The tutorial, with classes, is a bit intimidating

[krishnadevz]

i just updated hooks section for useState in functional component if anyone is maintainer here they can merge/review my pull request here 👉#2842