map and filter functions

map_and_filter.js

// map function
function array_map(arr,fn) {
  var rv = [];
  
  for(var i=0, l=arr.length; i<l; i++)
    rv.push(fn(arr[i]));
    
  return rv;
};

// filter function
function array_filter(arr,fn) {
  var rv = [];
  
  for(var i=0, l=arr.length; i<l; i++)
    if (fn(arr[i])) rv.push(arr[i]);

  return rv;
};