Nodejs Array Unique unique(mutate)

Method Source Code

/**/*from   w  w w. j  a va 2s  . c o  m*/
 * Remove duplicates from Array
 *
 * @Reference:
 * http://codereview.stackexchange.com/questions/60128/removing-duplicates-from-an-array-quickly
 * http://stackoverflow.com/questions/9229645/remove-duplicates-from-javascript-array/9229821#9229821
 */

Array.prototype.unique = function (mutate) {
  var unique = this.reduce(function (accum, current) {
    if (accum.indexOf(current) < 0) {
      accum.push(current);
    }
    return accum;
  }, []);
  if (mutate) {
    // Note: you cant assign `unique` variable to `this`, hence we make it's length to zero and push values to it.
    this.length = 0;
    for (var i = 0; i < unique.length; ++i) {
      this.push(unique[i]);
    }
    return this;
  }
  return unique;
};

// "Smart" but naive way
// Although concise, this algorithm is not particularly efficient for large arrays (quadratic time)
var uniqueArray = arr.filter(function (item, pos) {
  return arr.indexOf(item) === pos;
});

// Hashtables to the rescue
function uniq(a) {
  var seen = {};
  return a.filter(function (item) {
    return seen.hasOwnProperty(item) ? false : (seen[item] = true);
  });
}

// ES6 version
function unique(array) {
  return (new Set(array));
}

unique(b)

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

unique(callback)

Array.prototype.unique = function(callback) {
  var o = {}, i, l = this.length, r = [];
  for (i=0; i<l; i+=1) {
    var val = callback(this[i]);
    o[val] = this[i];
  for (i in o) {
    r.push(o[i]);
  return r;
};

unique(data)

Array.prototype.unique = function(data) {
  data.sort();
  var re = [ data[0] ];
  var length = data.length;
  for (var i = 1; i < length; i++) {
    if (data[i] !== re[re.length - 1]) {
      re.push(data[i]);
  return re;
};

unique(fun, map)

(
  Array.prototype.unique = function (fun, map) {
    fun = fun || (function(c) { return c; });
    var arrayUnique = [this[0]], 
    arrayUniqueAtt = [fun(this[0])];
    this.forEach(function(el){
      if (arrayUniqueAtt.indexOf(fun(el)) === -1) {
        arrayUniqueAtt.push(fun(el));
        arrayUnique.push(el);
...

unique(k)

Array.prototype.unique = function(k) {
    var self = this;
    var result = [];
    var sublen = 0;
    for (var i = 0, l = self.length; i < l; i++) {
        var v = self[i];
        if (!k) {
            if (result.indexOf(v) === -1) {
                result.push(v);
...

unique(str)

Array.prototype.unique = function(str){
  const seen = new Map()
  return this.filter((a) => {
    return !seen.has(a['name']) && seen.set(a['name'], 1)
  })

unique1()

Array.prototype.unique1 = function(){
  var res = [this[0]];
  for(var i = 1; i < this.length; i++){
    var repeat = false;
    for(var j = 0; j < res.length; j++){
      if(this[i] == res[j]){
        repeat = true;
        break;
    if(!repeat){
      res.push(this[i]);
  return res;
var arr = [1, 'a', 'a', 'b', 'd', 'e', 'e', 1, 0]
console.log(arr.unique1());

unique1()

Array.prototype.unique1 = function () {
  var a = [],
    o = {},
    n = this.length;
    for (var i=0; i<n; ++i) {
      o[this[i]] = this[i];
    for (var i in o) {
      a.push(o[i]);
...

unique2()

Array.prototype.unique2 = function(){
 this.sort(); 
 var res = [this[0]];
 for(var i = 1; i < this.length; i++){
  if(this[i] !== res[res.length - 1]){
   res.push(this[i]);
 return res;
...

Nodejs Array Unique unique(mutate)

Method Source Code

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