Nodejs Array Has Duplicate isDuplicate(val)

Method Source Code

/**//from w ww . j a v a 2 s . c  om
 * Test if a value is already contained in the array.
 * - Shallow search
 * - Compares primitives only
 *
 * return - True if the passed value is a already contained within the array,
 *          False otherwise.
 */
Array.prototype.isDuplicate = function(val) {
    for (var i = 0; i < this.length; i++) {
        var currentVal = this[i];
        if (currentVal === val) {
            return true;
        }
    }
    return false;
}

/* EOF */

Related

1. hasDuplicates()

   Array.prototype.hasDuplicates = function() {
       this.sort();
       for (var i = 1; i < this.length; i++) {
           if (this[i - 1] == this[i]) {
               return true;
       return false;
   };
   ...
   

2. hasDuplicates()

   Array.prototype.hasDuplicates = function() {
       for (var i = 0; i < this.length; i++) {
           var currentVal = this[i];
           for (var j = 0; j < this.length; j++) {
               if(i === j) continue; 
               var val = this[j];
               if (currentVal === val) {
                   return true;
       return false;