Inefficient, I know, since it’s probably better to break out of the for loop once you find your value but just having some fun!
As we all know, you can’t search an array using the in operator, but let’s force a square peg into a round hole. See if a value exists in an array using IN:
var test = ['one', 'two', 'three'];
'two' in (function (arr) { var o = {}; for(var x = 0; x < arr.length; x++) { o[arr[x]] = ''; } return o; } )(test); // Returns true
// Make it easier on yourself
var arrToObj = function (arr) { var o = {}; for(var x = 0; x < arr.length; x++) { o[arr[x]] = ''; } return o; };
// Now do it
'four' in arrToObj(test); // Returns false
The in operator is really used to search for a property of an object, but let's see if a value exists in an object using IN:
var test = {1: 'three', 2: 'two', 3: 'one'};
var objVals = function (obj) { var o = {}; for(var p in obj) { o[obj[p]] = '' }; return o; };
'three' in objVals(test); // Returns true
3 in objVals(test); // Returns false
Have fun coding!