Nodejs Utililty Methods Array Item Occurrence

Array.prototype.numberOfOccurrences = function( arg ) {
  var num = 0;
  this.forEach( function( e ){
    if ( arg === e ) { num++; }
  });
  return num;
};
var arr = [0,1,2,2,3,"a"];
console.log( arr.numberOfOccurrences("a") );
...

Array.prototype.numberOfOccurrences = function (arr) {
    var elem = 0;
    for (var i = 0; i < this.length; i++) {
        if (this[i] === arr) {
            elem++;
    return elem;
};
...

Array.prototype.numberOfOccurrences = function(chr) {
  return this.filter(function(x){ return x == chr; }).length;

Array.prototype.numberOfOccurrences = function(desVal) {
  var counter = 0;
  this.forEach(function(value){
    if(value === desVal){
      counter++;
  });
  return counter;
};
...

Array.prototype.numberOfOccurrences = function (el) {
  var count = 0;
  this.forEach(function (item) {
    if (item === el) count++;
  });
  return count;

Array.prototype.numberOfOccurrences = function(elem) {
  let obj = {};
  this.forEach(elem => elem in obj ? obj[elem]++ : obj[elem] = 1);
  return obj[elem] === undefined ? 0 : obj[elem]

Array.prototype.numberOfOccurrences = function(i) {
  var total = 0;
  this.filter(function (x) {
    if (i === x)
      total++;
  });
  return total;
};
var arr = [0,1,2,2,3];
...

Array.prototype.numberOfOccurrences = function(item) {
var drr = []; 
var i = 0 ;
   for(i = 0 ; i < this.length ; i++) {
       if(item=== this[i]){
           drr.push(this[i]); 
    return drr.length;
...

var arr = [4, 0, 4];
Array.prototype.numberOfOccurrences = function(item) {
  tmp = 0;
  for(var i=0; i<this.length; i++){
    if (item == this[i]) {
      tmp ++;
  console.log(tmp);
...

Array.prototype.numberOfOccurrences = function(n) {
  var counter = 0;
  for (i = 0; i < this.length; i++){
    if (n == this[i]){
      counter++;
  return counter;