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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 the simplified version of creator, which works like this:

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

var creator = function (name, options) {
    return partial(create, options.defaults);

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

In areas of 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.


BSD 2-clause license.