PubSub

[MartinKavik]

Resolves #130
Resolves #131

Changes

• Added methods subscribe, subscribe_with_handle, perform_cmd_with_handle, stream, stream_with_handle and notify into Orders (perform_cmd and Cancellation #130).
  • See comments for these methods in orders.rs.
  • They are demonstrated in the example subscribe.
  • You can stop stream / unsubscribe / cancel command by dropping its handle.
  • They should replace routes, window_events, sink and GMsg (they are not deprecated yet).
• Added cmds::timeout, stream::interval, stream::window_event, subs::UrlChanged and subs::UrlRequested (Easy timeout/setInterval #131).
• Added example subscribe.
• Updated example todomvc to use subscription UrlChanged instead of routes.
• [BREAKING] Futures in perform_cmd and perform_g_cmd are executed immediately.
  • It doesn't make sense to have it in the queue. Only output of send_msg(..) and notify(..) is pushed into the queue to prevent recursion and stack overflow in the update function.
• Added App methods notify and notify_with_notification.
• [BREAKING] App method process_cmd_and_msg_queue renamed to process_effect_queue.
• [BREAKING] Url change listeners are always active (even if routes is not defined).
  • To fire UrlChanged and UrlRequested notifications and to behave consistently.
• Added cmds, streams, subs, CmdHandle, SubHandle and StreamHandle into the Seed's prelude.
• [BREAKING] Removed module next_tick.
  • It was used internally to prevent potential stack overflow during spawn_local call, but it looks that it has been changed in the wasm_bindgen_futures - The future will always be run on the next microtask tick even if it immediately returns Poll::Ready. And tests that should check it pass so it should be ok. I assume that users don't use it, but it was probably available from the public API, so it's breaking change.

[theduke]

Much appreciated.