gistfile1.js

var assert = require('assert');

var reg = /\b(?:0x)?([A-Fa-f0-9])+\b/g;

assert.deepEqual('0x5f ff56'.match(reg), ['0x5f', 'ff56']);
assert.deepEqual('0x5f plain0x5ftext'.match(reg), ['0x5f']);
assert.deepEqual('0x5F DD52'.match(reg), ['0x5F', 'DD52']);
assert.deepEqual('Z4FD'.match(reg), null);

var Rectangle = function(l,h) {
  this.l = l;
  this.h = h;
}

Rectangle.prototype.getPerimeter = function() {
  return 2*this.l + 2*this.h;
}

Rectangle.prototype.getSurface = function() {
  return this.l*this.h;
}

var Square = function(l) {
  Rectangle.call(this, l, l);
}

Square.prototype.getPerimeter = Rectangle.prototype.getPerimeter;
Square.prototype.getSurface = Rectangle.prototype.getSurface;

var s = new Square(4);
console.log(s.getPerimeter())

var st = "<article:foo xmlns=f><title>Extensible Markup Language</title><title>Extensible Markup Language</title><para><acronym>XML</acronym> </para</article>";

var count = function(string) {
    return string.match(/<\w+/g)
                 .map(function(tag) {
                  return tag.substring(1);
                 })
                 .reduce(function(prev, current) {
                    prev[current] = (!prev[current]) ? 1 : prev[current] +1;
                    return prev;     
                 }, {});
};

console.log(count(st));

var fn = function(n) {
  if(fn.dyn[n])
    return fn.dyn[n];
  else {
    console.log(n)
    var res = 3*fn(n-1)-fn(n-2);
    fn.dyn[n] = res;
    return res;
  }
}

fn.dyn = {
  0 : 1,
  1 : 3
};

console.log(fn(5), fn(10));
console.log(fn.dyn);


leveException = function() {
  throw new Error('you are foo')
};

attrapeException = function() {
  try {
    leveException();
  } catch(e) {
    console.error('Ooopss : ' + e.message);
  }
};

attrapeException();