Nodejs Utililty Methods Array Unique

Array.prototype.unique = function() {
  return this.filter(function(item, idx, array) {
    return array.indexOf(item) === idx;
  });

Array.prototype.unique = function(){
    var array = [];
    for(var i = 0; i < this.length; i++) {
        if(!array.contains(this[i])) {
            array.push(this[i]);
    return array.compact();
};
...

Array.prototype.unique = function() {
  var uniques = [];
  this.forEach(function(value) {
    if (uniques.indexOf(value) == -1)
      uniques.push(value);
  });
  return uniques;
};

Array.prototype.unique = function() {
  return this.reduce(function(prev_val, current_val) {
    if (prev_val.indexOf(current_val) < 0) {
      prev_val.push(current_val);
    return prev_val;
  }, []);
};
Array.prototype.times_do = function(callback) {
...

Array.prototype.unique = function() {
    var a = [];
    for (var i = 0, l = this.length; i < l; i++)
        if (a.indexOf(this[i]) === -1)
            a.push(this[i]);
    return a;

Array.prototype.unique = function() {
  var a = this.concat();
  for(var i=0; i<a.length; ++i) {
    for(var j=i+1; j<a.length; ++j) {
      if(a[i] === a[j])
        a.splice(j--, 1);
  return a;
...

var numbers = [4,5,4,4,4,5,4,5]
function unique(arr) {
  var newArr = [];
  for (var i = 0; i < arr.length; i++) {
    if (newArr.indexOf(arr[i]) < 0) {
      newArr.push(arr[i]);
  return newArr;
...

Array.prototype.unique = function(){
   var u = {}, a = [];
   for(var l = 0, i = this.length-1; i >= 0; --i){
      if(u.hasOwnProperty(this[i])) {
         continue;
      a.unshift(this[i]);
      u[this[i]] = 1;
   return a;
};

Array.prototype.unique = function() {
  var key, output, value, _ref, _results;
  output = {};
  for (key = 0, _ref = this.length; 0 <= _ref ? key < _ref : key > _ref; 0 <= _ref ? key++ : key--) {
    output[this[key]] = this[key];
  _results = [];
  for (key in output) {
    value = output[key];
...

Array.prototype.unique = function () {
    return this.filter(function (value, index, array) {
        return array.indexOf(value) === index;
    });
};