Up next, systemjs.config.js which configures the SystemJS module loader.
The map block configures a module alias to a location or package. ‘app’ maps to the ./app directory. ‘rxjs’ maps to node_modules/rxjs, ‘angular2-in-memory-web-api’ maps to node_modules/angular2-in-memory-web-api, and ‘@angular’ maps to node_modules/@angular.
The packages block allows configuration of a particular map. ‘app’ is configured with a main of main.js and defaultExtension is set to js. ‘rxjs’ and ‘angular2-in-memory-web-api’ are configured with defaultExtension set to js as well.