jQuery Action Queue Sketch

action_queue.js

require([
  "jquery",
  "use!backbone",
  "use!underscore",
  "_s",
  "use!ui",
],

function($, Backbone, _, _s, ui){

    var actionSet = {
        //async: false,
        async: true,
        actions: [
            {
                type: 'action',
                def: {
                    type: 'log',
                    opts: {
                        msg: "Action1",
                        delay: 500
                    }
                }
            },
            {
                type: 'action',
                def: {
                    type: 'log',
                    opts: {
                        msg: "Action2",
                        delay: 200
                    }
                }
            }
        ]
    };

    // Takes an action definition, and returns an
    // action function.
    var processActionDef = function(actionDef){
        var action = null;
        if (actionDef.type == 'log'){
            action = function(){
                var deferred = $.Deferred();
                setTimeout(function(){
                    console.log("logging, ", actionDef.opts.msg);
                    deferred.resolve();
                }, actionDef.opts.delay);
                return deferred;
            };
        };

        return action;
    };

    var processActionSetDef = function(actionSetDef){

        var action = function(){
            var deferred = $.Deferred();

            // Assemble actions from definitions.
            var sub_actions = [];
            _.each(actionSetDef.actions, function(item){
                if (item.type == 'action'){
                    var sub_action = processActionDef(item.def);
                    sub_actions.push(sub_action);
                }
                else if (item.type == 'actionSet'){
                    console.log('actionSet');
                }
            });

            // If there were sub actions...
            if (sub_actions.length > 0){

                // Deferred representing final sub deferred.
                var final_sub_deferred = null;

                // If async, execute actions in parallel.
                if (actionSetDef.async){
                    console.log("async");
                    var sub_deferreds = [];
                    _.each(sub_actions, function(sub_action){
                        var sub_deferred = sub_action();
                        sub_deferreds.push(sub_deferred);
                    });
                    final_sub_deferred = $.when.apply($, sub_deferreds);
                }

                // Otherwise, execute actions in sequence.
                else{
                    // Initialize w/ first subaction.
                    final_sub_deferred = sub_actions[0]();
                    // Trigger subsequent subactions in sequence.
                    for (var i = 1; i < sub_actions.length; i++){
                        var i_ = i;
                        final_sub_deferred = final_sub_deferred.pipe(function(){
                            return sub_actions[i_]();
                        });
                    }
                }

                // When final deferred is complete, resolve.
                final_sub_deferred.done(function(){
                    deferred.resolve();
                });
            }
            // If there were no sub actions, resolve immediately.
            else{
                deferred.resolve();
            }

            return deferred;

        };

        return action;

    };

	$(document).ready(function(){
        console.log("document.ready");

        var action = processActionSetDef(actionSet);

        var dfd = action();
        dfd.done(function(){
            console.log("all done");
        });
	});

});