##UMD (Universal Module Definition)

The purpose of this repository is to centralize the information and work currently being done by a group in the community on UMD patterns. UMDs typically attempt to define modules which can work anywhere, be in in the client, on the server or anywhere else. This pattern typically attempts to offer compatibility with the most popular script loaders of the day (e.g RequireJS amongst others), and in many cases uses AMD as a base, with special-casing added to handle CJS compatability.

To date, a number of UMD variations have been proposed, ranging from Kit-Cambridge's UMD at [https://gist.github.com/1251221], through to patterns discussed by Addy Osmani, Thomas Davis and Ryan Florence and here [https://github.com/addyosmani/jquery-plugin-patterns/issues/1] and most recently the UMD patterns proposed by JR Burke here [https://gist.github.com/1262861]. The latter of these patterns will likely form the basis of the UMD we recommend actually using in production and more details about any proposed patterns will be documented as they're finalized.

###Variations

####Regular Module

• amdWeb.js - Defines a module that works with AMD and browser globals. If you also want to export a global even when AMD is in play (useful if you are loading other scripts that still expect that global), use amdWebGlobal.js.
• returnExports.js - Defines a module that works in Node, AMD and browser globals. If you also want to export a global even when AMD is in play (useful if you are loading other scripts that still expect that global), use returnExportsGlobal.js.
• commonjsStrict.js - Defines a module that works with more CommonJS runtimes, and for modules that will have a circular dependency. If you also want to export a global even when AMD is in play (useful if you are loading other scripts that still expect that global), use commonjsStrictGlobal.js

####jQuery Plugin

• jqueryPlugin.js - Defines a jQuery plugin that works with AMD and browser globals.
• jqueryPluginCommonjs.js - Defines a jQuery plugin that works with AMD and browser globals, but also in a CommonJS environment. However, jQuery is unlikely to run in most CommonJS environments, so only use this version if you know you are targeting a CommonJS environment that can load jQuery appropriately.

####AMD with simple Node/CommonJS adapter

These are useful for using AMD style while still making modules that can be used in Node and installed via npm without extra dependencies to set up the full AMD API.

This approach does not allow the use of AMD loader plugins, just basic JS module dependencies. It also does not support the callback-style require that is usable in AMD.

• nodeAdapter.js - Best for when using AMD style but want it to work in Node without a helper library that sets up AMD.
• commonjsAdapter.js - Similar to nodeAdapter.js, but compatible with more CommonJS runtimes, and if you want to define a circular dependency.

###Todos

• noConflict. Although with AMD loaders and build tools, it should be possible to get version specific bindings, maybe show a version that has a noConflict option.
• Variation with attaching some functionality to a $ impersonator. Although, it is tempting to say for that case, ask for 'jquery' as a dependency, and if the developer wants to use something different than the actual 'jquery', map that file to the 'jquery' name. That is one of the strengths of module names, they can be mapped to different implementations.
• Usage examples
  • Further justifications for usage
  • Gotchas/custom-tweaks we're aware of, but would rather not apply to the default UMD boilerplate

###Influences

The basic pattern for these UMD variations was derived from the approach @kriskowal used for the Q promise library.