Simple DI

di.js

var deps = {};

function register(name, value) {
  deps[name] = value;
}

function inject(fn) {
  var wants = fn.wants || [];
  var resolved = wants.map(resolve);
  return fn.apply(null, resolved);
}

function resolve(key) {
  var dep = deps[key];
  var injected = inject(dep);
  return injected;
}


register('name', function() {
  return 'joe';
});

register('greeter', (function() {
  function greeter(name) {
    return function() {
      console.log('yo ' + name);
    };
  }
  greeter.wants = ['name'];

  return greeter;
}()));


function myCoolThing(greeter) {
  return function() {
    console.log('before');
    greeter();
    console.log('later');
  };
}

myCoolThing.wants = ['greeter'];

var injected = inject(myCoolThing);
injected();