IOC

Maestro has a build in IOC framework.

It is simple, and tailored specifically to roku memory management and performance, as well as easy debugging using RALE tool.

Early on in your application, create your container and set instances as follows:

function initializeIOC()
  m.log.info("initializing the IOD container")
  'note this is done in the boostrap sequence in my apps
  mioc.createContainer()

  fontManager = createObject("roSGNode", "mv_FontManager")
  mioc.setInstance("fontManager", fontManager)

  styleManager = createObject("roSGNode", "mv_StyleManager")
  mioc.setInstance("styleManager", styleManager)
end function

To retrieve an instance, use mioc.getInstance("instance_name")

To retrieve an instance, use mioc.getInstance("instance_name", "path.to.some.data") , which will return the data on instance_name.path.to.some.data

You can override instances at any point with mioc.setInstance

You can inject ioc instances directly into your class fields, e.g.

class ButtonView extends mv.BaseView

@inject("styleManager")
private styleManager

@inject("user", "credentials.isLoggedIn")
private isLoggedIn

Maestro is all about testability, for this reason all the main base classes (e.g. NodeClass, BaseView, BaseViewModel, etc) have wrappers for mioc.setInstance and mioc.getInstance making them very easy to stub in a unit test. e.g.

extract from LoginScreenVM.spec.bs

  private function onRefreshComplete(result)
    m.log.method("onRefreshComplete", result)
    m.isLoading = false
    m.isMainGroupVisible = true

    if m.getInstance("user").isLoggedIn
      m.dismiss("success")
    else
      m.signalAppLaunchDialog(false)
      m.isRefreshing = false
    end if

  end function

extract from LoginScreenVM.bs

    '+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    @describe("onRefreshComplete")
    '+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

    @it("dismisses on successful refresh")
    function _()
      user = { "id": "user", isLoggedIn: true }
      m.expectOnce(m.vm, "getInstance", ["user"], user)
      m.expectOnce(m.vm, "dismiss", ["success"])

      m.vm.isLoading = true
      m.vm.isRefreshing = true

      m.vm.onRefreshComplete({})

    end function