angular-modules-as-js-modules.js

// services/calculator.js 
// contains a plain javascript object, which can be tested directly with mocha
 
var calculateResult = function (interest, duration, amount) {
    return …
};

module.exports = {
    calculateResult: calculateResult
};

// services/index.js 
// wraps the services definitions
// See https://nodejs.org/api/modules.html#modules_folders_as_modules for why we use an index.js

var angular = require('angular');
angular.module('calculatorModule', []).factory('Calculator', [function () { return require('./calculator') }]);

// We then use browserify to build the app.js by resolving all require(…) calls

Source of this idea: https://angularjs.de/artikel/angularjs-browserify