My app has several layers of nested components. Various components throughout the tree will need to interact with our API via http requests. If any API request returns a 401 - Not Authorized error, or a Timeout Error, the error needs to bubble up to the root component where is can be handled appropriately.
What is the most idiomatic way of dealing with this? *1. Parent should pattern match against important child messages*: Reference <https://groups.google.com/d/msg/elm-discuss/QPqrJd4C78Y/_TLLg81SAQAJ> This could work, but would be unreasonable in this case. The root component would need to match against every failing api http request made by every child, grandchild, great-grandchild, etc, component in the tree. If a single pattern is missed, the app would be in an error state, so this is prone to mistakes. *2. Nested Components return additional info from the "update" function*: Reference <http://stackoverflow.com/questions/37328203/elm-0-17-how-to-subscribe-to-sibling-nested-component-changes> Each component returns an additional value from its update function like this: update : Msg -> Model -> (Model, Cmd Msg, SomeInfo) The parent component could inspect the returned "SomeInfo" value from its direct children, and act on that information if necessary. In my case, any nested component that makes http requests to our API would be responsible for returning a APINotAuthorized and APITimeout value to its parent, and its parent would do the same, until the error has bubbled up to the root component. Option 2 is simple and robust, and can be used to pass messages of any type, for any situation... but I'm wondering if I'm missing an obvious 3rd solution? -- You received this message because you are subscribed to the Google Groups "Elm Discuss" group. To unsubscribe from this group and stop receiving emails from it, send an email to elm-discuss+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
