How to use JayData as the DataSource instead of JSON data?

<script>

// Fields for the grid data stored to a variable task.

        var Task = $data.define("Task", {

            OrderID: Number,

            CustomerID: String,

            Freight: Number

        });

 // Data for the field in the Grid can be given by using the .save() method.

        Task.save({

            OrderID: 123,

            CustomerID: 'BAS3000',

            Freight: 20

        });

</script>

<script>

Task.readAll().then(function (orderdetails) {

            $("#mobgrid").ejmGrid({

                dataSource: orderdetails,

                allowScrolling: true,

                allowPaging: true,

                columns: [

                         { field: "OrderID", headerText: "Order ID" },

                         { field: "CustomerID", headerText: "Customer ID" },

                         { field: "Freight", headerText: "Freight" }

                ]

            });

        });

    </script>