The most simple dependency injector

dependency-jockey.js

// mod.js

module.exports = function (dep1, dep2, rest) {
  /* ... */
}


// main.js

var dj = require('dependency-jockey')()
var mod = require('./mod')

function Dep1 () {}
function Dep2 () {}

dj.register('dep1', new Dep1)
dj.register('dep2', new Dep2)

// or

dj.register({
  dep1: new Dep1,
  dep2: new Dep2
})

var rest = 123

mod = dj(mod) // jock the deps

mod(rest) // mod is called with dep1, dep2 and rest


// dj.js

module.exports = function () {
  var deps = {}

  function dj (fn, ctx) {
    var depNames = fn.toString() // TODO: Reap arg names from fn

    return function () {
      var args = [].slice.call(arguments)
      var depArgs = depNames.map(function (name) {
        return deps[name]
      })
      return fn.apply(ctx, depArgs.concat(args))
    }
  }

  dj.register = function (name, obj) {
    if (obj) {
      deps[name] = obj
    } else {
      Object.keys(name).forEach(function (name, obj) { deps[name] = obj })
    }
    return dj
  }

  return dj
}