How to remove item from array 1 and push item to array 2

Question

What I try is to check the state.newCardArray and remove that item based on index and then push it to state.arrayFoldedCards. This is a card game, so if the newCardArray is empty and there is no winner or loser, then the game stops....

const initialState = {
  newCardArray: ['a', 'b', 'c']; // after removing the array looks like ['a', 'c']
  arrayFoldedCards: [] // pushing to the array resulted in an updated array that looks like ['b']
}

export const game = (state = initialState, action) => {
  switch (action.type) {
    case types.GET_CARD:
      {
        const getRandomNumber = Math.floor(state.newCardArray.length * Math.random());
        console.log(state.newCardArray);
        console.log(state.arrayFoldedCards);
        return {
          ...state,
          randomNumber: getRandomNumber,
          arrayFoldedCards: state.newCardArray[getRandomNumber].push(state.arrayFoldedCards.pop())
        }
      }
  }
}

Answer 1

Looks like you want something like splice/concat

var idxToRemove = 1; //Removing 'b'
var arr0 = ['a', 'b', 'c']; 
var arr1 = []; //Array to move to

return arr1.concat(arr0.splice(idxToRemove, 1));

Splice returns an array of removed elements so you can concat them together. Concat merges the two arrays without mutating either.

Answer 2

 case types.GET_CARD: { const indexToRemove = Math.floor(state.currentCardArray.length * Math.random()); const updatedArray = state.arrayFoldedCards.concat(state.currentCardArray.splice(indexToRemove, 1)); return { ...state, arrayFoldedCards: updatedArray } }