Nodejs Utililty Methods Array Sub

Array.prototype.allSubArrays = function allSubArrays(width) {
  var w = width;
  var allArr = [];
  var i;
  var len;
  if (w) {
    w = Math.min(w, this.length);
    for (i = 0, len = this.length - w + 1; i < len; ++i ) {
      allArr.push(this.slice(i, i + w));
...

Array.prototype.listsub = function (array, sizediff) {
    if (!array)
        return null;
  var match = [];
    for (var i = 0; i < this.length; i++) {
        if (this[i].contains(array, sizediff)) {
            match.push(this[i]);
    return match;

Array.prototype.sub = function(a2) {
  var l1 = this.length;
  var l2 = a2.length;
  var len = (l1 < l2 ? l1 : l2);
  var result = new Array(len);
  for (var i = 0; i < len; i++) {
    result[i] = this[i] - a2[i];
  return result;
...

Array.prototype.sub = function(other) {
    console.assert(this.length == other.length, 'sub: len(a) != len(b)');
    var ret = new Array(this.length);
    for(var i = 0; i < ret.length; i++)
        ret[i] = this[i] - other[i];
    return ret;

Array.prototype.subList = function(start, end){
  return this.slice(start, end);

Array.prototype.subset = function (field, criterion) {
  var arr = new Array();
  for (var i=0 ; i<this.length ; i++) {
    if(this[i][field] === criterion) {
      arr.push(this[i]);
  return arr;

Array.prototype.subsetOf = function (other) {
  for (var i = 0; i < this.length; i += 1) {
    if (other.indexOf(this[i]) === -1)
      return false;
  return true;
};