javascript function inArray

Question

I need a javascript function that can take in a string and an array, and return true if that string is in the array..

 function inArray(str, arr){
   ...
 }

caveat: it can't use any javascript frameworks.

Answer 1

You could just make an array prototype function ala:

Array.prototype.hasValue = function(value) {
  var i;
  for (i=0; i<this.length; i++) { if (this[i] === value) return true; }
  return false;
}

if (['test'].hasValue('test')) alert('Yay!');

Note the use of '===' instead of '==' you could change that if you need less specific matching... Otherwise [3].hasValue('3') will return false.

Answer 2

Take a look at this related question. Here's the code from the top-voted answer.

function contains(a, obj) {
  var i = a.length;
  while (i--) {
    if (a[i] === obj) {
      return true;
    }
  }
  return false;
}

Answer 3

Something like this?

function in_array(needle, haystack)
{
    for(var key in haystack)
    {
        if(needle === haystack[key])
        {
            return true;
        }
    }

    return false;
}