package js_of_ocaml-lwt

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Programming mouse or keyboard events handlers using Lwt

Reminder: Event capturing starts with the outer most element in the DOM and works inwards to the HTML element the event took place on (capture phase) and then out again (bubbling phase).

Examples of use:

Waiting for a click on elt1 before continuing:

let%lwt _ = Lwt_js_events.click elt1 in

Doing some operation for each value change in input element inp:

Lwt_js_events.(async (fun () ->
   clicks inp1 (fun ev _ -> ...)
))

Defining a thread that waits for ESC key on an element:

let rec esc elt =
 let%lwt ev = keydown elt in
 if ev##.keyCode = 27
 then Lwt.return ev
 else esc elt

Waiting for a click or escape key before continuing:

let%lwt () =
  Lwt.pick [(let%lwt _ = esc Dom_html.document in Lwt.return ());
            (let%lwt _ = click Dom_html.document in Lwt.return ())]
in ...

Create Lwt threads for events

make_event ev target creates a Lwt thread that waits for the event ev to happen on target (once). This thread is cancellable using <<a_api project="lwt" | val Lwt.cancel>> . If you set the optional parameter ~use_capture:true, the event will be caught during the capture phase, otherwise it is caught during the bubbling phase (default).

val seq_loop : (?use_capture:bool -> 'target -> 'event Lwt.t) -> ?cancel_handler:bool -> ?use_capture:bool -> 'target -> ('event -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t

seq_loop (make_event ev) target handler creates a looping Lwt thread that waits for the event ev to happen on target, then execute handler, and start again waiting for the event. Events happening during the execution of the handler are ignored. See async_loop and buffered_loop for alternative semantics.

For example, the clicks function below is defined by:

let clicks ?use_capture t = seq_loop click ?use_capture t

The thread returned is cancellable using <<a_api project="lwt" | val Lwt.cancel>> . In order for the loop thread to be canceled from within the handler, the latter receives the former as its second parameter.

By default, cancelling the loop will not cancel the potential currently running handler. This behaviour can be changed by setting the cancel_handler parameter to true.

val async_loop : (?use_capture:bool -> 'target -> 'event Lwt.t) -> ?use_capture:bool -> 'target -> ('event -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t

async_loop is similar to seq_loop, but each handler runs independently. No event is thus missed, but since several instances of the handler can be run concurrently, it is up to the programmer to ensure that they interact correctly.

Cancelling the loop will not cancel the potential currently running handlers.

val buffered_loop : (?use_capture:bool -> 'target -> 'event Lwt.t) -> ?cancel_handler:bool -> ?cancel_queue:bool -> ?use_capture:bool -> 'target -> ('event -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t

buffered_loop is similar to seq_loop, but any event that occurs during an execution of the handler is queued instead of being ingnored.

No event is thus missed, but there can be a non predictible delay between its trigger and its treatment. It is thus a good idea to use this loop with handlers whose running time is short, so the memorized event still makes sense when the handler is eventually executed. It is also up to the programmer to ensure that event handlers terminate so the queue will eventually be emptied.

By default, cancelling the loop will not cancel the (potential) currently running handler, but any other queued event will be dropped. This behaviour can be customized using the two optional parameters cancel_handler and cancel_queue.

val async : (unit -> 'a Lwt.t) -> unit

async t records a thread to be executed later. It is implemented by calling yield, then Lwt.async. This is useful if you want to create a new event listener when you are inside an event handler. This avoids the current event to be catched by the new event handler (if it propagates).

val func_limited_loop : (?use_capture:bool -> 'a -> 'b Lwt.t) -> (unit -> 'a Lwt.t) -> ?use_capture:bool -> 'a -> ('b -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t

func_limited_loop event delay_fun target handler will behave like Lwt_js_events.async_loop event target handler but it will run delay_fun first, and execut handler only when delay_fun is finished and no other event occurred in the meantime.

This allows to limit the number of events catched.

Be careful, it is an asynchrone loop, so if you give too little time, several instances of your handler could be run in same time *

val limited_loop : (?use_capture:bool -> 'a -> 'b Lwt.t) -> ?elapsed_time:float -> ?use_capture:bool -> 'a -> ('b -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t

Same as func_limited_loop but take time instead of function By default elapsed_time = 0.1s = 100ms *

Predefined functions for some types of events

This function returns the event, together with the numbers of ticks the mouse wheel moved. Positive means down or right. This interface is compatible with all (recent) browsers.

Returns when a CSS transition terminates on the element.

val transitionends : ?cancel_handler:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val clicks : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.mouseEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val dblclicks : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.mouseEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val mousedowns : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.mouseEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val mouseups : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.mouseEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val mouseovers : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.mouseEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val mousemoves : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.mouseEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val mouseouts : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.mouseEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val keypresses : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.keyboardEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val keydowns : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.keyboardEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val keyups : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.keyboardEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val inputs : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val timeupdates : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val changes : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val dragstarts : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.dragEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val dragends : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.dragEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val dragenters : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.dragEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val dragovers : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.dragEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val dragleaves : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.dragEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val drags : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.dragEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val drops : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.dragEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val mousewheels : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> ((Js_of_ocaml.Dom_html.mouseEvent Js_of_ocaml.Js.t * (int * int)) -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val touchstarts : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.touchEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val touchmoves : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.touchEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val touchends : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.touchEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val touchcancels : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.touchEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val focuses : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val blurs : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val scrolls : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val submits : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val selects : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val loads : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.imageElement Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val errors : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.imageElement Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val aborts : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.imageElement Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val canplays : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val canplaythroughs : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val durationchanges : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val emptieds : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val endeds : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val loadeddatas : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val loadedmetadatas : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val loadstarts : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val pauses : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val plays : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val playings : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val ratechanges : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val seekeds : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val seekings : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val stalleds : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val suspends : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val volumechanges : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val waitings : ?cancel_handler:bool -> ?use_capture:bool -> Js_of_ocaml.Dom_html.eventTarget Js_of_ocaml.Js.t -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val request_animation_frame : unit -> unit Lwt.t

Returns when a repaint of the window by the browser starts. (see JS method window.requestAnimationFrame)

Returns when the page is loaded

val domContentLoaded : unit -> unit Lwt.t
val onorientationchange : unit -> Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t Lwt.t
val onorientationchange_or_onresize : unit -> Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t Lwt.t
val onresizes : (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val onorientationchanges : (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val onpopstates : (Js_of_ocaml.Dom_html.popStateEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val onhashchanges : (Js_of_ocaml.Dom_html.hashChangeEvent Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val onorientationchanges_or_onresizes : (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val limited_onresizes : ?elapsed_time:float -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val limited_onorientationchanges : ?elapsed_time:float -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
val limited_onorientationchanges_or_onresizes : ?elapsed_time:float -> (Js_of_ocaml.Dom_html.event Js_of_ocaml.Js.t -> unit Lwt.t -> unit Lwt.t) -> unit Lwt.t
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