swapping values in react/redux - only works once - reactjs

Question

I am building a two player game in react/redux. There is always one player whose turn it is. The turn needs to change regularly between the two.
I have the following reducer. It works once, and then stops working.
case CHANGE_TURN:
if (playerTurn === 1) {
newPlayerTurn = 2;
newOtherPlayer = 1;
}
else {
newPlayerTurn = 1;
newOtherPlayer = 2;
}
return {
...state,
otherPlayerID: newOtherPlayer,
playerTurnID: newPlayerTurn
}
Since this part has worked in the past, I think perhaps something else is getting in the way????

Answer 1

I think the answer was accepted but you can also minimize your swapping operation by using:
[newPlayerTurn, newOtherPlayer] = [newOtherPlayer, newPlayerTurn];

Answer 2

Cloned your repo and checked it out.
Your players.js reducer, line 5 is:
let playerTurn = players.playerTurnID;
But should look like:
let playerTurn = state.playerTurnID;
You should get your playerTurn from your state object.

Answer 3

You might have forgotten to alternate playerTurn between 1 and 2 by returning it in the state. Also, the case can be simplified:
case CHANGE_TURN:
return {
...state,
playerTurn: state.playerTurn === 1 ? 2 : 1,
otherPlayerID: state.playerTurn === 1 ? 1 : 2,
playerTurnID: state.playerTurn === 1 ? 2 : 1,
};
playerTurn and playerTurnID are redundant btw, but maybe your example was simplified.
If it's strictly always exactly two players, one boolean is enough to model the entire state:
case CHANGE_TURN:
return { activePlayer: !state.activePlayer };
With an initialState of { activePlayer: false }. You could then write selectors like
const isPlayer1Active = (state) => !state.activePlayer; // false = player1's turn
const isPlayer2Active = (state) => state.activePlayer; // true = player2's turn
const getActivePlayerID = (state) => state.activePlayer ? 2 : 1;