welsonjs/lib/timer.js

/*
    Windows Scripting Host doesn't provide  setTimeout  and  clearTimeout.
    This serves as a replacement. 

    To use:

    Set up all the deferred actions you like with the usual setTimeout calls
       setTimeout(function() {
         // do something
       }, 200);

    Then call  setTimeout.queue.run(). 
    Deferred actions can spawn more deferred actions.
    If the queue ever runs dry, it will stop running and return.
    Remember, javascript is single-threaded. If you put more
    functions in the queue, call the run method again.
*/

exports.VERSIONINFO = "Timer Module (timer.js) version 0.1";
exports.global = global;
exports.require = global.require;

exports.sleep = function(ms, callback) {
    WScript.Sleep(ms);
    if(typeof(callback) == "function") {
        callback();
    }
};

exports.setTimeout = function(func, delay) {
    var when = new Date().getTime() + delay;
    return exports.setTimeout.queue.add(func, when);
};

exports.clearTimeout = function(timer) {
    exports.setTimeout.queue.del(timer);
};

// A queue object, with methods  add, del, run.
// Tied to setTimeout to keep it out of the global namespace.

exports.setTimeout.queue = (function() {
    var store = [];
    var nextid = 0;

    return {
        add: function(func, when) {
            store.push({
                id: nextid,
                func: func,
                when: when
            });
            return nextid++;
        },

        del: function(id) {
            for (var i = 0; i < store.length; i++) {
                if (store[i].id == id) {
                    store.splice(i, 1);
                }
            }
        },

        run: function() {
            while (store.length > 0) {
                var now = new Date().getTime();
                for (var i = 0; i < store.length; i++) {
                    var item = store[i];

                    if (now > item.when) {
                        exports.setTimeout.queue.del(item.id);
                        item.func(); //  <---- actually invoke the function here

                        // Note: we can't continue looping through the queue here, 
                        // because we removed one of the items. The loop limit is
                        // now incorrect. Easiest thing to do is restart the loop.

                        break;
                    }

                    // We burn a millisecond here to throttle the looping.
                    // Otherwise it will loop on the order of 200,000 times per sec.

                    exports.sleep(1);
                }
            }
        }
    }
})();

exports.setTimeout.test = function() {
    console.log('You should see: C,A,D,N,M');

    exports.setTimeout(console.log('A'), 500);
    var b = setTimeout(console.log('B'), 1220);
    exports.setTimeout(console.log('C'), 300);
    exports.setTimeout(console.log('D'), 1000);
    clearTimeout(b);

    exports.setTimeout(function() {
        console.log('N');
        exports.setTimeout(function() {
            console.log('M');
        }, 100)
    }, 1300);

    exports.setTimeout.queue.run();
    console.log('done');
};

/////  setTimeout.test();   // uncomment to run test