service-locator-demand

NodeJS based service locator with explicit dependency management. Useful to keep track of your dependencies throughout the project and enable good testability.

Install

$ npm install service-locator-demand

Usage

#### Setting and getting services

``js var locator = require('service-locator-demand');

locator.set('db', dbConnection); locator.set('app', app);

// ERROR: this key is already defined locator.set('db', anotherDbInstance);

// retrieve the instances again locator.db.loadSomething(); locator.app.toggleImportantStuff();

// unset instances and set them again locator.remove('db'); locator.set('db', anotherDbInstance);

// remove all instances locator.clear();

console.log(locator.db); // undefined`

#### Keep track of your dependencies

`js // ####> in your main module var locator = require('service-locator-demand'); locator.set('db', dbConnection); locator.set('app', myApp); locator.set('mail', myMailInstance);

// ####> in a satellite module var loc = require('service-locator-demand');

// #### Demand the services you want to have loc = loc.demand(module, 'db', 'app');

console.log(typeof loc.db); // --> 'object' console.log(typeof loc.app); // --> 'object'

// services which where NOT demanded, CANNOT be accessed console.log(typeof loc.mail); // --> undefined`

'loc' is a readonly copy (facade) for the real locator. If something changes in the locator those changes will be adopted by the copy.

#### Ensure that demanded modules are there

`js // ####> in a satellite module var loc = require('service-locator-demand');

// will throw exception because of 'nonExistentModule' loc = loc.demand(module, 'db', 'app', 'nonExistentModule');``

Tests

$ npm install -g grunt-cli
$ npm install
$ npm test

License

The MIT License