Execute the List Workflow using JSOM

Due to the requirement of application we were not allowed to run the List workflow on ItemCreated event or ItemChanged Event. So i have decided to go for a manual start of workflow.
But we cannot ask user to go the list select the item and start the workflow

So i have decided to start the workflow using the code on a button click for current list item.

For this we need the following Items

• List GUID
• Workflow Subscription GUID
• Get the Current Subscription
• Kick Off the Workflow

How to get the List GUID

function getListGUID() {

    var dfdcpname = $.Deferred(function () {

    var context = new SP.ClientContext.get_current();

    var web = context.get_web();

    var PROLIST = $("#hfProList").val(); //List Name

    var oList = web.get_lists().getByTitle(PROLIST);

    context.load(oList);

    context.executeQueryAsync(

         function () {

             dfdcpname.resolve(oList.get_id());

         },

         function (sender, args) {

             dfdcpname.reject(args.get_message());

         });

    });

    return dfdcpname.promise();

}

How to get the Workflow Subscription ID

function GetWorkflowid() {

    var dfdcpname = $.Deferred(function () {

        var context = SP.ClientContext.get_current();

        var web = context.get_web();

        var sMgr = new SP.WorkflowServices.WorkflowServicesManager(context, web);

        var wDefs = sMgr.getWorkflowDeploymentService().enumerateDefinitions();

        context.load(wDefs);

        context.executeQueryAsync(

        function () {

            var e = wDefs.getEnumerator();

            var subscriptionId = '';

            while (e.moveNext()) {

                var def = e.get_current();

                var workflowname = def.get_displayName();

                if (workflowname == 'Project Approval') {

                    subscriptionId = def.get_id();

                    break;

                    //StartWorkflow(subscriptionId, itemid);

                }

            }

            dfdcpname.resolve(subscriptionId);

        },

        function (sender, args) {

            dfdcpname.reject(args.get_message());

        });

    });

    return dfdcpname.promise();

}

Get the Current Subscription of Workflow

function StartWorkflow(subscriptionId, itemId) {

    var dfdcpname = $.Deferred(function () {

        var ctx = SP.ClientContext.get_current();

        var wfManager = SP.WorkflowServices.WorkflowServicesManager.newObject(ctx, ctx.get_web());

        var subscription = wfManager.getWorkflowSubscriptionService().enumerateSubscriptionsByDefinition(subscriptionId);

        ctx.load(subscription);

        ctx.executeQueryAsync(

            function (sender, args) {

                var subsEnum = subscription.getEnumerator();

                var sub = null;

                while (subsEnum.moveNext()) {

                    sub = subsEnum.get_current();

                    console.log('Subscription: ' + sub.get_name() + ', id: ' + sub.get_id());

                    dfdcpname.resolve(sub);

                    break;

                }

                dfdcpname.resolve(sub);

            },

            function (sender, args) {

                dfdcpname.reject(args.get_message());

            }

        );

    });

    return dfdcpname.promise();

}

Kick off the workflow on a List item

function StartWorkflowBySubscription(sub, itemId) {

    var dfdcpname = $.Deferred(function () {

        var ctx = SP.ClientContext.get_current();

        var wfManager = SP.WorkflowServices.WorkflowServicesManager.newObject(ctx, ctx.get_web());

        var initiationParams = {};

        wfManager.getWorkflowInstanceService().startWorkflowOnListItem(sub, itemId, initiationParams);

        ctx.executeQueryAsync(function (sender, args) {

            dfdcpname.resolve('Workflow Started');

        }, function (sender, args) {

            dfdcpname.reject(args.get_message());

        });

    });

    return dfdcpname.promise();

}

Register JS required for the Workflow

function StartWorkflowMain() {

    SP.SOD.executeFunc("sp.js", "SP.ClientContext", function () {

        SP.SOD.registerSod('sp.workflowservices.js', SP.Utilities.Utility.getLayoutsPageUrl('sp.workflowservices.js'));

        SP.SOD.executeFunc('sp.workflowservices.js', "SP.WorkflowServices.WorkflowServicesManager", StartListWorkflow);

    })

}

Start List Workflow function

function StartListWorkflow() {

    GetItemIdByProjectName().done(function (ItemId) {

        GetWorkflowid().done(function (subscriptionId) {

            StartWorkflow(subscriptionId, ItemId).done(function (sub) {

                StartWorkflowBySubscription(sub, ItemId).done(function (messg) {

                    console.log(messg);

                });

            });

        });

    });

}