jsoo_broadcastchannel 1.1 · OCaml Package

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 https://developer.mozilla.org/en-US/docs/Web/API/BroadcastChannel
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

package jsoo_broadcastchannel

Exceptions and types

Common functions

Event support