app.js

"use strict";

require("angular");
require("angular-route");
var home = require("./controllers/home");
var testService = require("./services/testService");

angular.module("app", ["ngRoute"])
    .config(function ($routeProvider) {
        $routeProvider.when("/", {
            templateUrl: "./templates/home.html"
        })
        ;
    })
    .controller("home", home)
    .factory("testService", testService);

home.js

"use strict";

function home(testService) {
    var vm = this;
    vm.title = "hello world";

    testService.someMethod();
}

module.exports = home;

testService.js

"use strict";

function testService() {

    return {
        someMethod: function() {
            console.log("called someMethod");
        }
    }
}

module.exports = testService;