Easiest way to handling indexOf

Lets create a function that allow us to if string is available in array with this shortcode

function checkStringInArray(arrayItem, stringItem) {
  return !!~arrayItem.indexOf(stringItem);
}

using tilde operator will flip the bits in its operand. which is similar to

  -(x+1)

then use !! to convert this into boolen, this is easiest way to check indexOf and its more readable than …

  arrayItem.indexOf(stringItem) > -1