javascript - 如何正确使用indexOf来检查数组中是否有某些内容

Question

我想在这个猜谜游戏中检查用户输入的颜色是否在数组列表中。但是当你输入列表中的颜色时，它一直说它不是

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;
  }
}

Answer 1

你的条件是倒退的:

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;
}

在某些情况下您还需要返回 true 以避免无限循环。