AppScript QML Type

• List of all members, including inherited members

Properties

• runWhen : string
• running : bool
• script : script

Signals

• finished(int returnCode)
• started()

Methods

• exit(int returnCode)
• on(var type, func callback)
• chian once(var type, func callback)
• run()

Detailed Description

AppScript is a helper component to handle asynchronous sequential workflow. The immediate benefit of using AppScript is the centralisation of code in a place. Instead of placing them within onXXXX code block in several components in several places.

AppScript also manage the life cycle of registered callbacks. You could remove them by a single function. Nothing will leave in memory.

Remarks: AppScript is not a solution for making Store component

Example Code

AppScript {
    // Run this script if "Pick Image" button is clicked.
    runWhen: ActionTypes.askToPickPhoto

    script: {
        // Step 1. Open file dialog
        dialog.open();

        // Register a set of callbacks as workflow
        // Registered callbacks will be executed once only per script execution
        once(dialog.onAccepted, function() {

            // Step 2. Once user picked an image, launch preview window and ask for confirmation.
            AppActions.navigateTo(imagePreview,
                                  {source: dialog.fileUrl});

        }).then(ActionTypes.pickPhoto, function(message) {
            // The function of then() is same as once() but it won't
            // trigger the callback until once() is triggered.

            // Step 3. Add picked image to store and go back to previous page.

            PhotoStore.add(String(message.url));

            AppActions.navigateBack();

        }); // <-- You may chain then() function again.

        // Condition to terminate the workflow:
        // Force to terminate if dialog is rejected / or navigateBack is dispatched
        // That will remove all the registered callbacks

        once(dialog.onRejected,exit.bind(this,0));

        once(ActionTypes.navigateBack,exit.bind(this,0));
    }
}

Benefit of using AppScript

• Centralize your workflow code in one place
• Highly integrated with AppDispatcher. The order of callback execution is guaranteed in sequence order.
• Only one script can be executed at a time. Registered callbacks by previous script will be removed before starting.
• exit() will remove all the registered callbacks. No callback leave after termination.

Why not just use Promise?

• 1. You need another library. (e.g QuickPromise)
• 2. You need to set reject condition per callback/promise

Explanation:

Coding in a promise way requires you to handle every reject condition correctly. Otherwise, promise will leave in memory and their behaviour will be unexpected. AppScript::run() / AppScript::exit() clear all the registered callback completely. You can write less code.

Property Documentation

Signal Documentation

Method Documentation

AppScript {

    script: {

        once(ActionTypes.askToRemoveSelectedItem, funciton() {

            removeConfirmationDialog.open();

        }).then(removeConfirmationDialog.onAccepted, function() {

            AppActions.removeSelectedItem();

        }); // <-- You may chain then() function again.
    }
}