Is item in array?

Hub — Thu, 25 Mar 2021 11:06:29 +0000

Task: Check if item is in array. Return boolean.

function forHas(arr, x) {
  for (let item of arr) {
    if (item === x) {
      return true;
    }
  }
  return false;
}

function compareHas(arr, x) {
  return arr.indexOf(x) !== -1;
}

function includesHas(arr, x) {
  return arr.includes(x);
}

function someHas(arr, x) {
  return arr.some(item => item === x);
}

If you want to don't understand your code.

function bitwiseHas(arr, x) {
  return !!~arr.indexOf(x);
}

~-1 === 0, then !!0 === false, any other number than 0 is truthy.

function setHas(arr, x) {
  return new Set(arr).has(x);
}

function filterHas(arr, x) {
  return !!arr.filter(item => x === item).length; // 😂
}

function reduceHas(arr, x) {
  return arr.reduce(function (has, item) {
    if (!has) return item === x;
    return has;
  }, false); // 💣
}

What piece of code are you using for that task? What is the strangest, but efficient way to do that?

DEV Community: Hub