Dependency injection idea

dependency-injection-idea.js

function createFactory() {
  var args = [].slice.call(arguments);
  var createFunc = args.pop();
  return function() {
    if (arguments.length > 0) {
      return createFunc.apply(null, arguments);
    } else {
      return createFunc.apply(null, args);
    }
  };
}

var depA = {my: 'depA'};
var depB = {my: 'depB'};

var module = {
  create: createFactory(depA, depB, function(depA, depB) {
    return {
      key: 'value',
      depA: depA
    };
  })
};

// in your code
var instanceWithoutDeps = module.create();

// in test
var testDepA = {test: 'depA'};
var testDepB = {test: 'depB'};
var instanceWithDeps = module.create(testDepA, testDepB);

Idea came from delivering a module that contains all the default dependencies. Normally you have the dependencies outside and you have to care about collecting those in the default case, when you want to use it somewhere else. Maybe it is a good idea for the bootstrap/factory code, where you assemble your dependencies.

About the DOM problem: my assumption is that all dependencies are wrapped in a function so that a require-call would not hit the underlying service.