Keep beforeAction for shared code between methods

[karellm]

Hi,

I've seen this in the exemple app/docs:

class MyController extends Controller
    beforeAction: (route, params) ->
        # some shared code for all methods
        if route.method is 'method1'
            # do something

    method1: ->
        # render method 1

What do you guys think of having a beforeMethod1 method in the controller?

class MyController extends Controller
    beforeAction: (route, params) ->
        # some shared code for all methods

    beforeMethod1: ->
        # render method 1

    method1: ->
        # render method 1

I like that the logic for method1 stays grouped with method1. Plus it doesn't break current implementations.

[paulmillr]

This is not the primary use case for that. You don't need beforeMethod1, you can do this stuff in method1.

[karellm]

Ok maybe I am mistaken here. Isn't on major benefit of the beforeAction to make sure data is available before rendering?

I could see this useful to implement transition between views. We can ensure before* is done before initiating the transition.

For instance, do you consider this piece of code following the Chaplin way?

beforeAction: (params, route) ->
    $.when(super).then =>
        if route.action is 'signup'
            @promise = $.ajax # an api call

    if @promise and @promise.always
        @promise.always () => @publishEvent 'hidePageLoading'
    else
        @publishEvent 'hidePageLoading'

    return @promise

signup: (params) ->
    @promise.done (data) =>
        # new view

    @promise.fail (error) =>
        # handle error

[paulmillr]

Isn't on major benefit of the beforeAction to make sure data is available before rendering?

As a some universal way of checking this — maybe, but I never used it like that.

Personally in apps I develop I don't handle fetch errors much. If something is wrong then it's really wrong and a user should report to site admin. As for loading indicators, i'd rather did them in views.

[karellm]

In this case it is not really a fetch but a verification to an api. I have to handle the error, to either redirect or display an error message.

I'm curious to know how you handle transitions though. In my case, I have this @publishEvent 'hidePageLoading' that will hide a loader that cover the entire page on initial page load. Though I haven't get to implement nice transition between route changes after that (it is often hard to notice the route actually changed).

[paulmillr]

We don't handle them...transitions are long time in TODO list, they will be awesome to implement some day!

[karellm]

1/ How do you handle the data fetching then? I guess for models you rely on the new SyncMachine but no all data and async calls may be tied to a model. Do you have a sample code of this?

2/ Is there an draft on transitions already? I will need transitions in my app so I'd be interested in tackling this feature.

[paulmillr]

it's like this all the time:

action: (params) ->
  @model = new User {id: params.id}
  @view = new UserView {@model}
  @model.fetch().then @view.render

see gh-105