Nodejs Utililty Methods Array Max

Array.prototype.max = function (fun) {
    var max = this[0];
    this.forEach(x => {
        if (fun ? fun(max, x) : (max < x))
            max = x;
    });
    return max;
};

Array.prototype.max = function (func) {
    return func === undefined ? Math.max.apply(null, this) : Math.max.apply(null, this.select(func));
};

Array.prototype.max = function (k) {
  return Math.max.apply (null, this.column (k));
};

Array.prototype.max = function (prop) {
    var max = prop ? this[0][prop] : this[0];
    var len = this.length;
    for (var i = 1; i < len; i++) {
        var item = prop ? this[i][prop] : this[i];
        if (item > max) {
            max = item;
    return max;
};

Array.prototype.max = function (s) {
  s = s || Selector;
  var l = this.length;
  var max = s(this[0]);
  while (l-- > 0)
    if (s(this[l]) > max) max = s(this[l]);
  return max;
};

Array.prototype.max = function(selector){
  var maxItem = this[0];
  var maxValue = -999999;
  this.forEach(function(item){
    var value = selector(item);
    if( value > maxValue ){
      maxItem = item;
      maxValue = value;
  });
  return maxItem;

Array.prototype.maxima = function() {
  for(var i = 0, maxValue = Number.MIN_VALUE; i < this.length; i++) {
    parseInt(this[i]) > maxValue && (maxValue = this[i]);
  return maxValue
var arr = [1,21,3,4,22,45,6,7,32];
console.log(arr.join("|") + ":" + arr.maxima());

Array.prototype.maxima = function(){
  for (var i = 0, maxValue = Number.MIN_VALUE; i < this.length; i++) {
    parseInt(this[i]) > maxValue &&  (maxValue = this[i])
  };
  return maxValue
var arr = [1,21,3,4,22,45,6,7,32];
console.log(arr.join("+")+"="+arr.sum());
console.log(arr.join("|")+" "+arr.maxima());
...

'use strict';
Array.prototype.maximum = function () {
  return this.reduce(function (max, aValue) {
    return Math.max(max, aValue);
  }, this[0]);
};

Array.prototype.maximum = function()
    var max = this[0];
    for(el in this)
        if(this[el] > max)
            max = this[el] ;
    return max ;
};