Fable : Help for Action

File1.fs

let load tilesheetJsonPath (callback: Action) () =
    let mutable tilesheet : TilesheetJson = createEmpty<TilesheetJson>

    let loadImg (tilesheet: TilesheetJson) () =
        let img = document.createElement_img()
        img.onload <- Func<_,_>(fun e ->
            let c = document.createElement_canvas()
            let ctx = c.getContext_2d()
            // Set directly (no css) the width and height of the canvas
            // To ensure to draw the whole image. Otherwise, the browsers seems to
            // set the size to 300*150
            c.width <- img.width
            c.height <- img.height
            // Store the image in the canvas
            ctx.drawImage (U3.Case1 img, 0., 0.)
            callback.Invoke()
            null
        )
        img.src <- tilesheet.Tilesheet.Path

    ajax (Get tilesheetJsonPath)
        (fun data ->
            let tilesheet = Serialize.ofJson<TilesheetJson> data
            loadImg tilesheet ()
            //cache?(tilesheet.Tilesheet.Name) <- tilesheet
            )
        (fun error ->
            console.error ((sprintf "Error when loading %s" tilesheetJsonPath), status))

// Init the cache for the Tilesheet.
let init (tilesheets: string list) () =

    for i = 0 to tilesheets.Length do
        let current = tilesheets.Item(i)
        let cb () =
            console.log "coucou"
        load current (Action cb) () |> ignore

File1.js

var load = $exports.load = function (tilesheetJsonPath, callback, unitVar2) {
        var tilesheet = {};

        var loadImg = function (tilesheet_1) {
            return function (unitVar1) {
                var img = document.createElement('img');

                img.onload = function (e) {
                    var c, ctx;
                    return c = document.createElement('canvas'), ctx = c.getContext('2d'), c.width = img.width, c.height = img.height, ctx.drawImage(img, 0, 0), callback(), null;
                };

                img.src = tilesheet_1.Tilesheet.Path;
            };
        };

        (0, _Utils.ajax)(new _Utils.HttpMethod("Get", tilesheetJsonPath), function (data) {
            return function () {
                var tilesheet_1;
                return tilesheet_1 = _fableCore.Util.ofJson(data), loadImg(tilesheet_1)();
            }();
        }, function (error) {
            console.error(function () {
                return function () {
                    var clo1;
                    return clo1 = _fableCore.String.fsFormat("Error when loading %s")(function (x) {
                        return x;
                    }), function (arg10) {
                        return clo1(arg10);
                    };
                }();
            }()(tilesheetJsonPath), status);
        });
    };

var init = $exports.init = function (tilesheets, unitVar1) {
    for (var i = 0; i <= tilesheets.length; i++) {
        var current = _fableCore.Seq.item(i, tilesheets);

        var cb = function (unitVar0) {
            console.log("coucou");
        };

        load(current, cb());
    }
};