https://codepen.io/Franz92/pen/VQQNmV?editors=0010
I’m creating a react version of a calculator and I’ve come across a setState problem. If you try it out, you will see, that math operation buttons need two clicks to add a class. Would be very happy, if someone could help me, thank you 
What class are you adding and why? Do you mean CSS class or JS class?
I’m adding CSS class with help of classNames library. I want to highlight the operation, when user selects it. I’ll also use bool value of the state to execute operation, when equals buttons is clicked.
I have split up callback functions based on their functionality and now it suddenly updates on first click…
Decimal points don’t work.