service-locator/service-locator.js

service-locator helps keep your system decoupled by providing a central location where your application information can be found by other parts of you application.

/**
 * Paul Serby <paul.serby@clock.co.uk>
 *
 * New BSD Licensed
 *
 * Thursday 12 Jan 2012
 *
 */
module.exports = function createServiceLocator() {

	var self = {}

	/**
	 * Registers a service and make it read only
	 * @param {String} name To get the service by
	 * @param {Object} service What you want to register
	 */
	function register(name, service) {

		if (!name) {
			throw new Error('You must provide a valid name for this service.')
		}

		if (self[name] !== undefined) {
			throw new Error('Service \'' + name + '\' already registered')
		}

		if (!service) {
			throw new Error('You must provide a valid service for \'' + name + '\'')
		}

		Object.defineProperty(self, name, {
			configurable: false,
			get: function() { return service },
			set: function() {
				throw new Error('You can not alter a registered service \'' + name + '\'')
			}
		})

		return self
	}

	self.register = register
	return self
}