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Module BroadcastChannel

module BroadcastChannel: sig .. end
jsoo_broadcastchannel provides a wrapper around the BroadcastChannel API in JavaScript. The BroadcastChannel interface represents a named channel that any browsing context of a given origin can subscribe to. It allows communication between different documents (in different windows, tabs, frames or iframes) of the same origin. Messages are broadcasted via a message event fired at all BroadcastChannel objects listening to the channel.

Example of use :

Creating a channel an post message (on a first file) : 

      let channel = BroadcastChannel.create "my_first_channel"
      let _ = BroadcastChannel.post channel (Js.string "Hello World")

Receiving message from the channel my_first_channel on an another file with onmessage function : 

      (* Retreive the channel *)
      let channel : Js.string Js.t BroadcastChannel.t = 
        BroadcastChannel.create "my_first_channel"
      (* You have to fix the type of the channel, you can also use [BroadcastChannel.create_with] *)

      let _ = 
        BroadcastChannel.on
          channel 
          (fun ev -> 
            (* Use the ev object *)
            Js._true
          )

Receiving message from the channel my_first_channel on an another file with addEventListener function : 

      (* Retreive the channel *)
      let channel : Js.string Js.t BroadcastChannel.t = 
          BroadcastChannel.create "my_first_channel"
      (* You have to fix the type of the channel, you can also use [BroadcastChannel.create_with] *)

      let _ = 
        BroadcastChannel.addEventListener
          channel
          (BroadcastChannel.message channel)
          (Dom.handler (fun ev -> ... Js._true))
          Js._true

Or you can use BroadcastChannel.create_with (for a more conveinent usage) 

      (* Retreive the channel *)
      let (channel, message_event) = 
        BroadcastChannel.create_with 
          "my_first_channel"
          (Js.string "a sample")

      let _ = 
        BroadcastChannel.addEventListener
          channel
          message_event
          (Dom.handler (fun ev -> ... Js._true))
          Js._true

Receiving message from the channel my_first_channel on an another file with Lwt_js_events : 

      (* Retreive the channel *)
      let channel : Js.string Js.t BroadcastChannel.t = 
        BroadcastChannel.create "my_first_channel"

      let _ = 
        Lwt_js_events.async_loop 
          BroadcastChannel.lwt_js_message
          channel
          (fun ev _ -> 
            ... 
            Lwt.return_unit
          )

See also The BroadcastChannel API

Exceptions and types


exception Not_supported
Exception if BroadcastChannel is not supported
class type ['message] messageEvent = ['message] EventSource.messageEvent
Class type to define a messageEvent 
type 'a message = 'a messageEvent Js.t
Shortcut for a messageEvent
class type ['message] broadcaster = object .. end
Interface of a BroadcastChannel 
type 'a t = 'a broadcaster Js.t
Shortcut for a broadcaster

Common functions


val is_supported : unit -> bool
Returns true if BroadcastChannel is supported by the client's browser, false otherwise.
val create : string -> 'message t
Creates a BroadcastChannel with a name. Raise Not_supported "BroadcastChannel" if BroadcastChannel is not supported by the client's browser.
val create_with : string ->
       'a -> 'a t * 'a message Dom.Event.typ
Creates a BroadcastChannel with a name. Raise Not_supported "BroadcastChannel" if BroadcastChannel is not supported by the client's browser. The functions takes a "sample of a message" to fix the types of the broadcaster. The functions returns a couple of the BroadcastChannel and the Event (to be used) in addEventListener.
val close : 'message t -> unit
Closes the channel object, indicating it won't get any new messages, and allowing it to be, eventually, garbage collected.
val name : 'message t -> string
Returns a string, the name of the channel.
val post : 'message t -> 'message -> unit
Sends the message, of the broadcaster type to each BroadcastChannel object listening to the same channel.
val on : 'message t ->
       ('message message -> bool Js.t) -> unit
Is an EventHandler property that specifies the function to execute when a message event is fired on this object.

Event support


val addEventListener : 'a t ->
       'a message Dom.Event.typ ->
       ('a t, 'a message) Dom.event_listener ->
       bool Js.t -> Dom.event_listener_id
Add an event listener. This function matches the addEventListener DOM method, except that it returns an id for removing the listener.
val message : 'a t -> 'a message Dom.Event.typ
An event to be used with addEventListener
val lwt_js_message : ?use_capture:bool ->
       'a t -> 'a messageEvent Js.t Lwt.t
An event to be used with Lwt_js_events