CODEWITHSUNDEEP
javascriptarraysindexof
Kevin Deconinck
Kevin Deconinck

Reputation: 1

how to use indexOf proper to check if something is in the array

I want to check in this guessing game if the color the user inputs is in the array list or not. but when u put a color that is in the list it keeps saying it isn't

var guess_input;
var target;
var colors = ["blue", "cyan", "gold", "gray", "green", "magenta", "orange",
  "red", "white", "yellow"
]
var finished = false;
var guesses = 0;
var pos;


function do_game() {
  var random_number = Math.floor(Math.random() * (colors.length - 1));
  target = colors[random_number];

  while (!finished) {
    guess_input = prompt("I am thinking of one of these colors: \n\n" + colors.join() +
      "\n\n What color am I thinking of?");
    guesses++;
    finished = check_guess();
  }
}

function check_guess() {
  if (colors.indexOf(guess_input) > -1) {
    alert(
      "This is not a color from the list ! Please pick a color from the list\n\n"
    );
    return false;
  }
}

Upvotes: 0

Views: 155

Answers (2)

William B
William B

Reputation: 1419

Your conditional is backwards:

function check_guess() {
  if (colors.indexOf(guess_input) === -1) { // -1 means not found! you have > -1 which means found!
    alert(
      "This is not a color from the list ! Please pick a color from the list\n\n"
    );
    return false;
  }
  else return true;
}

You also need to return true in some case to avoid an infinite loop.

Upvotes: 3

DLeh
DLeh

Reputation: 24395

To check if the input is not in the list, you want == -1, not > -1.

  if (colors.indexOf(guess_input) == -1) {
    //the element was not found

Upvotes: 2

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