state

I have something to do for work and I need your help. We want to implement a FSM - Finite State Machine , to identify char sequence(like: A, B, C, A, C), and tell if it accepted. We think to implement three classes: State , Event and Machine . The state class presents a node in the FSM , we thought to implement it with State design pattern , every node will extend from the abstract class state and every class would handle different types of events and indicate transitions to a new state. Is it good idea in your opinion? Second thing, we don't know how to save all the transitions. Again we

What's the major difference bewteen these two functions? handleOnChange(evt) { this.setState(() => ({ tickerName: evt.target.value })); } handleOnChange(evt) { this.setState({ tickerName: evt.target.value }); } And why with the handleOnChange() function that change the state directly this works fine? <input type="text" value={this.state.tickerName} onChange={(evt) => this.handleOnChange(evt)} /> When I use the first function that change the state with a callback I get this error: TypeError: evt.target is null These are two different syntaxes for setState First: handleOnChange(evt) { this

I've recently been learning about functional programming (specifically Haskell, but I've gone through tutorials on Lisp and Erlang as well). While I found the concepts very enlightening, I still don't see the practical side of the "no side effects" concept. What are the practical advantages of it? I'm trying to think in the functional mindset, but there are some situations that just seem overly complex without the ability to save state in an easy way (I don't consider Haskell's monads 'easy'). Is it worth continuing to learn Haskell (or another purely functional language) in-depth? Is