Fancy Instances

fancy-instances.js

// Proto-classy
function Book ( a_auth, a_email, options ) { var author, email
  this.options = options || {}
  this.options.__proto__ = Book.options

  author = a_auth
  email = a_email

  accessor.call( this, 'author'
    , function() { return 'Author: ' + author }
    , function( a_auth ) { author = a_auth }
  )

  accessor.call( this, 'email'
    , function() { return 'Email: ' + email }
    , function( a_email ) { email = a_email }
  )

  // Instance methods
  this.publish = function( url ) { }

  this.update = function() { }

  // Private methods
  function accessor ( name, get, set ) {
    this.__defineGetter__( name, get )
    this.__defineSetter__( name, set )
  }
}

Book.options =
  { read: false
  , rating: 5
  , published: false
  }

// Usage
var jPad = new Book( 'Douglas Koopland', 'dougie@coupland.net' )

// Dynamic inheritence for options
console.log( jPad.options.rating ) // 5
Book.options.rating = 7
console.log( jPad.options.rating ) // 7
jPad.options.rating = 10
console.log( jPad.options ) // { rating: 10 }

// Accessors
console.log( jPad.author ) // "Author: Douglas Koopland"
jPad.author = 'Douglas Coupland'
console.log( jPad.author ) // "Author: Douglas Coupland"

screenshot.png

If you want ruby-style accessors, then you could clean up this implementation a bit:

accessor.call( this, 'author' )
accessor.call( this, 'email' )

// Later...
function accessor ( name ) {
  this.__defineGetter__( name, function(){ return this[ name ] } )
  this.__defineSetter__( name, function( value ){ this[ name ] = value } )
}