Closed
Description
Proposed changes (1st draft):
Replace App::builder with:
App::start("app", init, update, view);"app"implementsMountPoint/RootEl.updateandviewwithout changes.initexample:
fn init(url: Url, &mut impl Orders<Msg>) -> Model {
orders.subscribe(subs::UrlChanged, Msg::UrlChanged);
Model::default()
}New behavior:
- Seed looks for
<base>element in<head>and eventually sets base url for its router according tobase'shref. (Base for routing #369) - Seed tries to
hydrate/overtakeHTML in its mount point / root element. If it's not possible, fallbacks torender/append. (Mount takeover behavior concerns. #277) - You can simulate
UrlHandling::PassToRoutesby:
fn init(url: Url, &mut impl Orders<Msg>) -> Model {
orders.subscribe(subs::UrlChanged, Msg::UrlChanged).notify(subs::UrlChanged(url));
Model::default()
}Motivation
- PubSub API was introduced in this PR. It makes
routes,window_events,sinkandGMsgredundant. So it's a good time to revisit and improve App builder API. - Builder API is too complex:
- I don't remember all function signatures so I have to often copy-paste them from app_builder example.
- We need a dedicated example (
app_builder) for it to demonstrate all options. - I often forget to "register" some functions in the builder and then I'm surprised that my app doesn't work.
- It's harder to read in docs and maintain.
- There are very cryptic compiler error messages - e.g. when you forgot to implement
Defaultfor yourModel(Improve error message when Model doesn't implement Default #376). - There are many implicit options, Seed-specific names and calls, probably confusing for beginners -
UrlHandling,MountType,Model::default(if it's possible),BeforeMount,AfterMount,sink..
- I don't know why I should want to use
urlinBeforeMount. BeforeMountandAfterMountcan be confusing - I would think that it meansBefore mounting to DOMandAfter mounting to DOM- which is not true because it hasn't been rendered yet. Also it deviates from standard Elm architecture and doesn't make sense in submodules context.
Implementation notes
- Remove comment at
UrlChange-/// - Url change is fired also on application start by default.