Some recursive functions...for learning.

funkshun.js

var funkshun = (function(){
  var concat = Array.prototype.concat;
  
  function replicate(n, x){   
    return n===0 ? [] : concat.call(replicate(--n, x),x);    
  }
  
  function take(n, arr){      
    function _take(n, arr){      
      var head;          
      if(n <= 0 || !arr.length) return [];
      
      head = arr.shift();    
      if(typeof arr[0] === 'function') arr = arr[0]();
      return concat.call(head, _take(--n, arr));  
    }
    return _take(n, arr.slice());
  }

  function reverse(arr){
    function _reverse(arr){
      var head;
      if(!arr.length) return [];      
      head = arr.shift();
      return concat.call(_reverse(arr), head);
    }
    return _reverse(arr.slice());
  }
  
  function maximum(arr){
    function _maximum(arr){      
      var head;
      if(!arr.length) throw 'You can\'t get the maximum value of an empty array.';
      if(arr.length === 1) return arr[0];      
      head = arr.pop();
      return Math.max(head, _maximum(arr));
    }
    return _maximum(arr.slice());
  }
    
  function repeat(val){
    return concat.call(val,function(){return repeat(val);});
  }
  
  return{
    take: take,
    reverse: reverse,
    maximum: maximum,
    replicate: replicate,
    repeat: repeat    
  };
}());


var arr = [1,2,3,5,4];
var threes = funkshun.repeat(3);
console.log(funkshun.take(500, threes));
console.log(funkshun.maximum([2,4,6,1,7,20,3,0]));
console.log(funkshun.take(3, arr));
console.log(funkshun.replicate(10, 0));