The multiStepContainer directive is the starting point. Each multiStepContainer has its own instance
of a MultiStepForm object (provided by the multiStepForm factory) which provide controls such has: start,
nextStep, previousStep, finish, cancel, etc...
Form step elements are created with the help of the formStepElement factory. Each form step controller
(if provided) gets the MultiStepForm instance of its container available to inject (dependency is called
multiStepFormInstance). In addition, each form step scope is augmented with the following functions
from its multiStepFormInstance (with a $ prefix): MultiStepForm.cancel(), MultiStepForm.finish(),
MultiStepForm.getActiveIndex(), MultiStepForm.setActiveIndex(), MultiStepForm.getActiveStep(),
MultiStepForm.nextStep(), MultiStepForm.previousStep() and MultiStepForm.setValidity().
Each MultiStepForm object has a start method which is invoked by the multiStepContainer directive in its postLink function. It returns a promise for avoiding an inversion of control:
- If the
MultiStepForm.cancel()method is called, the promise is rejected and the onCancel callback is executed. - If the
MultiStepForm.finish()method is called, the promise is resolved and the onFinish callback is executed. - The promise receives a notification each time there is a step change. The current form step element is destroyed and a new one is created.