Nodejs Utililty Methods Random Number Get

Math.iRandom = function(a, b){
  if (arguments.length == 1){
    return Math.round(Math.random() * a);
  }else if (arguments.length == 2){
    return a + Math.round(Math.random() * (b - a));
};

Math.rand = function (l, u) {
  return Math.floor((Math.random() * (u - l + 1)) + l);
};

Math.rand = function(min, max) { 
  return Math.floor(Math.random() * (max - min) + min); 

Math.range = function (a, b) {
  return this.floor(this.random() * a) + b;
};

 function random(_minNum,_maxNum,_rejArr){
     var minNum=_minNum||4,
         maxNum=_maxNum||17,
         rejArr=_rejArr||[],
         num=-1,
         flag=true;
     num = Math.floor(Math.random()*(maxNum-minNum+1)+minNum);
     if(rejArr.length>maxNum-minNum) return -1;
     for(var i=0,len=rejArr.length;i<len;i++){
...

function random(low, high) {
  var rand = (Math.random() * high) + low;
  return rand;

function random(min, max) {
    return Math.floor(Math.random() * (max - min)) + min;

function random(min, max) {
   return Math.floor(Math.random() * (max - min + 1)) + min;

function random(min, max) {
  return Math.floor(Math.random() * max) + min;

randomBetween = function(N, M) {
  return Math.floor(M + (1 + N - M) * Math.random());
};