creator.js

A tiny library for creating create-methods for your objects.

These are some things I like:

• Using Object.create.
• Having objects with their own create method.
• Create-methods that take named parameters.
• Failing early.

Creator.js helps with this. Instead of writing:

var banana = {
    create: function (params) {
      if (!params) { throw new TypeError("banana.create: missing params { color, brand }"); }
      if (!params.color) { throw new TypeError("banana.create: missing param { color }"); }
      if (!params.brand) { throw new TypeError("banana.create: missing param { brand }"); }

      return Object.extend(Object.create(this), params);
    }
};

You have:

var banana = {
    create: creator("banana", ["color", "brand"])
};

Or if you need more options:

var banana = {
    create: creator("banana", {
        required: ["color", "brand"],
        defaults: { curvature: 23 },
        strict: true
    }
};

In which

• required is a list of parameters that are required,
• defaults is a list of parameters that are optional with defaults, and
• strict makes it complain about unknown parameters.

Won't someone think of the performance

In a production environment, you can use a much simplified version of creator, pretty much like this:

var create = function (params) {
    return Object.extend(Object.create(this), params);
};

var creator = function () { return create; };

That way you get meaningful error messages and early failures while developing and testing, without sacrificing performance in production.

In areas of the code that needs to be highly optimized, you should of course use whatever is optimized better by current JavaScript engines . At the time of writing that would be the pseudo-classical function constructors and new.

Dependencies

Right now creator.js is dependent on lodash, a drop-in replacement for underscore that has a suite of unit tests, supports AMD and to top it off has some significant performance improvements.

I am considering removing the dependency given enough pressure to do so. :-P

License

BSD 2-clause license. http://www.opensource.org/licenses/bsd-license.php