make it work in strict mode

[sibelius]

https://reactjs.org/docs/strict-mode.html

• [ ] it should not use the old react context

My recommendation is to avoid classes and move to functions and hooks

[Vitao18]

Hey Can I help on this issue?

[sibelius]

send pull request

[a-x-]

Hey, you're awesome, guys! Thanks for you job.

I reviewed all the changed files, but still not tried to run it.

We'll released alpha version after PR be merged, so we be able to check new it on our projects