Clean configuration defaults via Object.create in Node.js

While recently coming back to clean up some Node.js module code I was looking for a nicer way to handle configuration of an object besides doing something like this to handle both configuration options and defaults.

var MyModule = function(opts){
  this.foo = opts.foo || 1;
  this.bar = opts.bar || 2;
  // the list goes on
}

In my opinion this code is not really readable, and defaults are not as obvious as I would like them to be. So I decided to let myself get inspired from jQuery which provides a nice way to handle settings and defaults in plugins, via $.extend(defaults, options) so my first Idea was to simple create an extend function in node, but since I would have to extend Object to make this as clean as possible I was looking for a way to handle this natively, and this is where Object.create comes in handy.

Object.create allows creating of an object based on some prototype as well as some default values, which is exactly what I was looking for. Do to the way Object.create handles properties the options need to be prepared before merging them in the configuration, which is finally bound to this.

var MyModule = function(opts){
  // some default values 
  var defaults = { foo: 1, bar: 2 };

  // prepare the options for Object.create
  var options = {};
  for(var i in opts){
    options[i] = { 
      value: opts[i], 
      enumerable: true, 
      writeable: true, 
      configurable: true } 
    };
  }

  // let Object.create merge the options with the defaults
  var config = Object.create(defaults, options);

  // bind to this
  for(var o in config){
    this[o] = config[o];
  }
}

Any suggestions for a different cleaner handling of configuration options are highly welcome.

EDIT: Fixed extra level of nesting in options thanks to Sami Samhuri

1 month ago  Notes (17)
  1. sideshowcoder-main posted this
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