var Swap = function (array, item1, item2){ 
if (item1 === item2) { 
return ; 
} 
var index1 = array.indexOf(item1); 
var index2 = array.indexOf(item2); 
if (index1 < 0 || index2 < 0) { 
throw new Error('Supplied items must be elements of the same array')
} 
array[index1] = item2; 
array[index2] = item1; 
return array; 
} 
; 
module.exports = Swap;