Nodejs Utililty Methods Array Max

Array.prototype.max = function(){
  var a = this;
  var max = 0;
  for(var x = 1;x<a.length;x++)
    if(a[x]>a[max])
    max = x;
  return a[max];

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

Array.prototype.max = function() {
  var max = this[0];
  for (var i = 0; i < this.length; i++) if(this[i] > max) max = this[i];
  return max;
};
Array.prototype.min = function() {
  var min = this[0];
  for (var i = 0; i < this.length; i++) if(this[i] < min) min = this[i];
  return min;
...

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

Array.prototype.max = function() {
  var maxval = 0;
  for (var i=0; i<this.length;i++) {
    var val = Number(this[i]);
    if (!isNaN(val)) {
      maxval = Math.max(maxval, val);
  return maxval;
...

Array.prototype.max = function() {
  var max = -Infinity;
  for (var i = 0; i < this.length; i++) {
    if (typeof this[i] === "number" && this[i] > max) {
      max = this[i];
  return max;
};
...

Array.prototype.max = function() {
  if (this.toNumsOnly().length == 0) return undefined;
  return Math.max.apply(null, this.toNumsOnly());
};

Array.max = function( array ){
    return Math.max.apply( Math, array );
};

Array.prototype.max = function(c) {
        c = c || function(a, b) { return a > b ? a : b; };
        m = this[0];
        for(var i = 1; i < this.length; i++) {
                m = c(this[i], m);
        return m;
};

Array.prototype.max = function(comparer) {
    if (this.length === 0) return null;
    if (this.length === 1) return this[0];
    comparer = (comparer || Math.max);
    var v = this[0];
    for (var i = 1; i < this.length; i++) {
        v = comparer(this[i], v);
    return v;
...