Really small JavaScript class library

tiny_klass.js

function extend() {
  return Array.prototype.reduce.call(arguments, function(acc, el) {
    for (var k in el) if (el.hasOwnProperty(k)) acc[k] = el[k];
    return acc;
  });
}

function klass(parent, props) {
  var F = (props && props.init) || function() { return parent.apply(this, arguments); };
  F.prototype = extend(Object.create(parent.prototype), props);
  F._super = F.prototype._super = parent;
  return F;
}

/* Usage example:

var Silly = klass(Object, {
  init: function(name) {
    this.name = name;
    this.greet();
  },
  greet: function() {
    console.log("Hi, I'm", this.name);
  }
});

var Polite = klass(Silly, {
  init: function(name) {
    Polite._super.call(this, name);
    console.log("Nice to meet you!");
  }
});

var Pedant = klass(Polite, {
  greet: function() {
    console.log("I'm known by the name of", this.name);
  }
});

var s = new Silly("Sam");
var p = new Polite("Peter");
var q = new Pedant("Mr. McChicken");

*/