##Pathway

####JavaScript library package system inspired by Go modules

This is a bare bones tool to achieve high-level modules in JavaScript. The aim is to define a convention for wiring up modular code in a way that is flexible and as uncomplicated as possible.

The approach is to separate modules from script loading and make the bootstrap process up-front and synchronous.

Pathway is intended for use in projects with a build system. Pathway itself has minimal code to facilitate being inlined for deployment.

API

Define a pathway library

var root = {};
makePathway('myLib', root);
root['@myLib'];
// => function pathway() {...}

root here is your designated global object. It could be window, or some sort of sandbox.

Add a package closure:

root['@myLib']('some/pkg', function ($import, $package) {
	var p = $import('some/other/pkg'); // import within library
	var p2 = $import('@libTwo/external/pkg'); // import from another pathway lib
	var underscoreLib = $import('@_'); // global reference fall back

	$package.ourSecret = 'shared package private value';

	return {
		exportedField: 'exported public value'
	};
});

The module ‘some/pkg’ can have as many of these closures as needed. The exported fields are merged into a module API object. Key conflicts will throw an error.

Import from outside:

root['@myLib'].import('some/pkg');
// => { exportedField: 'exported public value' }

Nothing more to it.

Import between libraries & global dependencies

Simple-as-possible mechanism for combining separate libraries. It is synchronous and does not support circular imports.

Method 1. Providers

• Function defined on the root object using '@' prefix

• It is invoked with a path

    $import('@myLib/utils') => root['@myLib']('/utils')
  

Method 2. Global libs

• Named property on the root object

• Fall-back if a provider function was not found

    $import('@jQuery') => root.jQuery
  

$import therefore, removes any practical need for direct global references in your library.

Notes

• A module is defined using one or more initialization functions
• '$package' is an object shared by closures within the same package
• Any JavaScript object can be used as 'root' object (eg window), so long as inter library dependencies are reachable through that object
• Like Go, circular dependencies between modules are not supported (or desired)
• Initialization order only matters within modules that use own package references during init.

Links

• Pathway Build Files
• Gulp integration gulp-pathway
• Go naming conventions, Effective Go
• Dependency Inversion, Wikipedia