try_q/try08.html at master · anglee/try_q · GitHub

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<!DOCTYPE html>
<html>
<head>
    <title>I promised I will try Q</title>
    <script src="./lib/q/q-20130830/q.js"></script>
    <script src="./utils.js"></script>
    <script>
        var evaluate1 = function () {
            utils.log("ev1");
            var ev1_step1 = function () {
                utils.log("ev1_step1 started");
                var deferred_step1 = Q.defer();
                Q.delay(1000).then(function () {
                    utils.log("ev1_step1 finished");
                    deferred_step1.resolve();
                });
                utils.log("return ev1_step1");
                return deferred_step1.promise;
            };
            var ev1_step2 = function () {
                utils.log("ev1_step2 started");
                var deferred_step2 = Q.defer();
                Q.delay(1000).then(function () {
                    utils.log("ev1_step2 finished");
                    deferred_step2.resolve();
                });
                utils.log("return ev1_step2");
                return deferred_step2.promise;
            };
            var deferred = Q.defer();
            Q.delay(1000)
                    .then(ev1_step1)
                    .delay(1000)
                    .then(ev1_step2)
                    .delay(1000)
                    .then(function () {
                        utils.log("done ev1");
                        deferred.resolve("output from ev1");
                    });
            utils.log("return ev1");
            return deferred.promise;
        };

        var evaluate2 = function (input) {
            utils.log("ev2, input of ev2 =", input);
            Q.delay(1000).then(function () {
                utils.log("async ev2");
            });
            utils.log("return ev2");
            return "output from ev2";
        };

        Q.fcall(evaluate1)// Q.fcall returns a Promise obj, since evaluate1 returns promise, this line could be just evaluate1()
                .delay(1000)
                .then(evaluate2);
    </script>
</head>
<body>
Check console.
</body>
</html>