WTF is this? http://bost.ocks.org/mike/chart/

constructor.js

// This will create constructed instances that can be easily extended 

function Chart( width, height ) {
  if ( !(this instanceof Chart) ) {
    return new Chart( width || null, height || null );
  }
  this.width = width || 720;
  this.height = height || 80;

  // construct your charts here...
}

Chart.prototype.width = function( value ) {
  if ( !arguments.length ) return this.width;
  this.width = value;
  return this;
};

Chart.prototype.height = function( value ) {
  if ( !arguments.length ) return this.height;
  this.height = value;
  return this;
};

wat.js

// This is JUST a function object with "static" expando properties

function chart() {
  var width = 720, // default width
      height = 80; // default height

  function my() {
    // generate chart here, using `width` and `height`
  }

  my.width = function(value) {
    if (!arguments.length) return width;
    width = value;
    return my;
  };

  my.height = function(value) {
    if (!arguments.length) return height;
    height = value;
    return my;
  };

  return my;
}