tictactoe game, player 2 error with an if statement to put a piece

Question

I am trying to do a tictactoe game using browser console, step by step, and at the end improve my functions. However, i am stuck at the player 2 turn(ttt_player2_turn()), I have to check if the case is empty or not. It's seems i have a problem with arguments in this exemple. Thanks for your advices(there is lodash functions). Edit : Now the problem in the function is that it's doesn't verify the is_case_free statement.

// to have a printed board
function ttt_print_board(array){
  return ('\n' +
        ' ' + array[0] + ' | ' + array[1] + ' | ' + array[2] + '\n' +
        ' ---------\n' +
        ' ' + array[3] + ' | ' + array[4] + ' | ' + array[5] + '\n' +
        ' ---------\n' +
        ' ' + array[6] + ' | ' + array[7] + ' | ' + array[8] + '\n')
}

//display things
function ttt_display(stuff){
  console.log(stuff)
}

//ask something
function ttt_ask(question) {
  return prompt(question)
}

// to verify if the answers is between 1-9
function ttt_verify_response(response) {
  var integer_response = _.toInteger(response)
  if(integer_response < 10 && integer_response > 0 && _.isInteger(integer_response)){
    return true
  } else {
    return false
  }
}

// this is my function to verify if case empty or not, at the moment just for 'x'
function ttt_verify_case (board, response) {
  if(board[response] === 'x' ){
  return false
  } else{
  return true
  }
}

// return the player 1 choice
function ttt_player1_turn() {
  var response = 0;
  var is_correct_response = false
  while(! is_correct_response){
    response = ttt_ask("player 1 it's your turn (play 1 to 9)")
    is_correct_response = ttt_verify_response(response)
  }
  return response
}

//return the player 2 choice and have to check if the case is empty from 'x', it seems like it doesn't go through the 2nd if condition
function ttt_player2_turn(board) {
  var is_correct_response = false
  var is_case_free = false
  while(!is_correct_response || !is_case_free){
    var response_player2 = ttt_ask("player 2 it's your turn, play 1 to 9");
    is_correct_response = ttt_verify_response(response_player2)
    if (!is_correct_response) {
      console.log("incorrect response")
      continue
    }
    is_case_free = ttt_verify_case(board, response_player2);
    if(!is_case_free) {
      console.log("player 1 already put a piece on this case")
    }
  }
  return response_player2
}


//main function
function ttt_new_game() {
  var board = [' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ']
  var printed_board = ttt_print_board(board)
  ttt_display(printed_board)
  board[_.toInteger(ttt_player1_turn()) - 1] = 'x'
  ttt_display(ttt_print_board(board))
  board[_.toInteger(ttt_player2_turn()) - 1] = 'o'
  ttt_display(ttt_print_board(board))
}

Answer 1

There are two things that I have found in relation to your problem:

First, in ttt_verify_case, you use assignment (=) instead of equality check (===) in an if statement. Second, you do not subtract 1 from the response (response is in [1;9], board has domain [0;8]). It should be:

// this is my function to verify if case empty or not, at the moment just for 'x'
function ttt_verify_case (board, response) {
  if (board[response - 1] === 'x') {
    return false;
  } else {
    return true;
  }
}

In the future you will want to change this into a switch statement to handle both the x and the o cases.

The second problem is that you never actually check whether the case is empty for player 2. You set var is_case_free = false and never call ttt_verify_case. In fact you are not passing board to ttt_player2_turn, so it cannot actually verify that the case is free anyway.

And finally, you never actually pass board to ttt_player2_turn in ttt_new_game.

An additional comment on your code: terminate all of your statements with semicolons.

There are a few changes you might want to make, but I will show you the changes I would make to ttt_player2_turn:

// Get player 2's move
function ttt_player2_turn(board) {
  var is_correct_response = false;
  var is_case_free = false;
  // Keep asking the player for a response until it is valid
  while (!is_correct_response || !is_case_free) {
    var response_player2 = ttt_ask("player 2 it's your turn, play 1 to 9");
    // Make sure that the response is valid
    is_correct_response = ttt_verify_response(response_player2);
    if (!is_correct_response) {
      console.log("incorrect response");
      continue; // loop again
    }
    // Make sure that the case is free
    is_case_free = ttt_verify_case(board, response_player2);
    if(!is_case_free) {
      console.log("player 1 already put a piece on this case");
    }
  }
  return response_player2;
}

Answer 2

I found my mistake, since it is an array i forget in my ttt_verify_case to -1 the response.

// this is my function to verify if case empty or not, at the moment just for 'x'
function ttt_verify_case (board, response) {
  if(board[response - 1] === 'x' ){
  return false
  } else{
  return true
  }
}