Node.js Alexa skill: alexa-sdk or alexa-app?

alexa-sdk-fsm-original.js

// Original code snippet from https://github.com/alexa/skill-sample-nodejs-decision-tree/blob/master/src/index.js
// set state to start up and  welcome the user
var newSessionHandler = {
  'LaunchRequest': function () {
    this.handler.state = states.STARTMODE;
    this.emit(':ask', welcomeMessage, repeatWelcomeMessage);
  },'AMAZON.HelpIntent': function () {
    this.handler.state = states.STARTMODE;
    this.emit(':ask', helpMessage, helpMessage);
  },
  'Unhandled': function () {
    this.handler.state = states.STARTMODE;
    this.emit(':ask', promptToStartMessage, promptToStartMessage);
  }
};

// --------------- Functions that control the skill's behavior -----------------------

// Called at the start of the game, picks and asks first question for the user
var startGameHandlers = Alexa.CreateStateHandler(states.STARTMODE, {
    'AMAZON.YesIntent': function () {

        // ---------------------------------------------------------------
        // check to see if there are any loops in the node tree - this section can be removed in production code
        visited = [nodes.length];
        var loopFound = helper.debugFunction_walkNode(START_NODE);
        if( loopFound === true)
        {
            // comment out this line if you know that there are no loops in your decision tree
             this.emit(':tell', loopsDetectedMessage);
        }
        // ---------------------------------------------------------------

        // set state to asking questions
        this.handler.state = states.ASKMODE;

        // ask first question, the response will be handled in the askQuestionHandler
        var message = helper.getSpeechForNode(START_NODE);

        // record the node we are on
        this.attributes.currentNode = START_NODE;

        // ask the first question
        this.emit(':ask', message, message);
    },
    'AMAZON.NoIntent': function () {
        // Handle No intent.
        this.emit(':tell', goodbyeMessage);
    },
    'AMAZON.StopIntent': function () {
        this.emit(':tell', goodbyeMessage);
    },
    'AMAZON.CancelIntent': function () {
        this.emit(':tell', goodbyeMessage);
    },
    'AMAZON.StartOverIntent': function () {
         this.emit(':ask', promptToStartMessage, promptToStartMessage);
    },
    'AMAZON.HelpIntent': function () {
        this.emit(':ask', helpMessage, helpMessage);
    },
    'Unhandled': function () {
        this.emit(':ask', promptToStartMessage, promptToStartMessage);
    }
});


// user will have been asked a question when this intent is called. We want to look at their yes/no
// response and then ask another question. If we have asked more than the requested number of questions Alexa will
// make a choice, inform the user and then ask if they want to play again
var askQuestionHandlers = Alexa.CreateStateHandler(states.ASKMODE, {

    'AMAZON.YesIntent': function () {
        // Handle Yes intent.
        helper.yesOrNo(this,'yes');
    },
    'AMAZON.NoIntent': function () {
        // Handle No intent.
         helper.yesOrNo(this, 'no');
    },
    'AMAZON.HelpIntent': function () {
        this.emit(':ask', promptToSayYesNo, promptToSayYesNo);
    },
    'AMAZON.StopIntent': function () {
        this.emit(':tell', goodbyeMessage);
    },
    'AMAZON.CancelIntent': function () {
        this.emit(':tell', goodbyeMessage);
    },
    'AMAZON.StartOverIntent': function () {
        // reset the game state to start mode
        this.handler.state = states.STARTMODE;
        this.emit(':ask', welcomeMessage, repeatWelcomeMessage);
    },
    'Unhandled': function () {
        this.emit(':ask', promptToSayYesNo, promptToSayYesNo);
    }
});

// user has heard the final choice and has been asked if they want to hear the description or to play again
var descriptionHandlers = Alexa.CreateStateHandler(states.DESCRIPTIONMODE, {

 'AMAZON.YesIntent': function () {
        // Handle Yes intent.
        // reset the game state to start mode
        this.handler.state = states.STARTMODE;
        this.emit(':ask', welcomeMessage, repeatWelcomeMessage);
    },
    'AMAZON.NoIntent': function () {
        // Handle No intent.
        this.emit(':tell', goodbyeMessage);
    },
    'AMAZON.HelpIntent': function () {
        this.emit(':ask', promptToSayYesNo, promptToSayYesNo);
    },
    'AMAZON.StopIntent': function () {
        this.emit(':tell', goodbyeMessage);
    },
    'AMAZON.CancelIntent': function () {
        this.emit(':tell', goodbyeMessage);
    },
    'AMAZON.StartOverIntent': function () {
        // reset the game state to start mode
        this.handler.state = states.STARTMODE;
        this.emit(':ask', welcomeMessage, repeatWelcomeMessage);
    },
    'DescriptionIntent': function () {
        //var reply = this.event.request.intent.slots.Description.value;
        //console.log('HEARD: ' + reply);
        helper.giveDescription(this);
      },

    'Unhandled': function () {
        this.emit(':ask', promptToSayYesNo, promptToSayYesNo);
    }
});

alexa-sdk-fsm-refactored.js

// Refactored code snippet from alexa-sdk-fsm-original.js
function welcome() {
    this.handler.state = states.STARTMODE;
    this.emit(':ask', welcomeMessage, repeatWelcomeMessage);
}

function help() {
    this.handler.state = states.STARTMODE;
    this.emit(':ask', helpMessage, helpMessage);
}

function startOver() {
    this.handler.state = states.STARTMODE;
    this.emit(':ask', promptToStartMessage, promptToStartMessage);
}

function goodbye() {
        this.emit(':tell', goodbyeMessage);
}

// set state to start up and  welcome the user
var newSessionHandler = {
  'LaunchRequest': welcome,
  'AMAZON.HelpIntent': help,
  'Unhandled': startOver
};

// --------------- Functions that control the skill's behavior -----------------------

// Called at the start of the game, picks and asks first question for the user
var startGameHandlers = Alexa.CreateStateHandler(states.STARTMODE, {
    'AMAZON.YesIntent': function () {

        // ---------------------------------------------------------------
        // check to see if there are any loops in the node tree - this section can be removed in production code
        visited = [nodes.length];
        var loopFound = helper.debugFunction_walkNode(START_NODE);
        if( loopFound === true)
        {
            // comment out this line if you know that there are no loops in your decision tree
             this.emit(':tell', loopsDetectedMessage);
        }
        // ---------------------------------------------------------------

        // set state to asking questions
        this.handler.state = states.ASKMODE;

        // ask first question, the response will be handled in the askQuestionHandler
        var message = helper.getSpeechForNode(START_NODE);

        // record the node we are on
        this.attributes.currentNode = START_NODE;

        // ask the first question
        this.emit(':ask', message, message);
    },
    'AMAZON.NoIntent': goodbye,
    'AMAZON.StopIntent': goodbye,
    'AMAZON.CancelIntent': goodbye,
    'AMAZON.HelpIntent': help,
    'Unhandled': startOver
});

// user will have been asked a question when this intent is called. We want to look at their yes/no
// response and then ask another question. If we have asked more than the requested number of questions Alexa will
// make a choice, inform the user and then ask if they want to play again
var askQuestionHandlers = Alexa.CreateStateHandler(states.ASKMODE, {
    'AMAZON.YesIntent': function () {
        // Handle Yes intent.
        helper.yesOrNo(this,'yes');
    },
    'AMAZON.NoIntent': function () {
        // Handle No intent.
         helper.yesOrNo(this, 'no');
    },
    'AMAZON.StopIntent': goodbye,
    'AMAZON.CancelIntent': goodbye,
    'AMAZON.StartOverIntent': welcome,
    'Unhandled': function () {
        this.emit(':ask', promptToSayYesNo, promptToSayYesNo);
    }
});

// user has heard the final choice and has been asked if they want to hear the description or to play again
var descriptionHandlers = Alexa.CreateStateHandler(states.DESCRIPTIONMODE, {
 'AMAZON.YesIntent': welcome,
    'AMAZON.NoIntent': goodbye,
    'AMAZON.StopIntent': goodbye,
    'AMAZON.CancelIntent': goodbye,
    'AMAZON.StartOverIntent': welcome,
    'DescriptionIntent': function () {
        //var reply = this.event.request.intent.slots.Description.value;
        //console.log('HEARD: ' + reply);
        helper.giveDescription(this);
      },
    'Unhandled': function () {
        this.emit(':ask', promptToSayYesNo, promptToSayYesNo);
    }
});

alexa-sdk-fsm-refactored.min.js

function welcome(){this.handler.state=states.STARTMODE,this.emit(":ask",welcomeMessage,repeatWelcomeMessage)}function help(){this.handler.state=states.STARTMODE,this.emit(":ask",helpMessage,helpMessage)}function startOver(){this.handler.state=states.STARTMODE,this.emit(":ask",promptToStartMessage,promptToStartMessage)}function goodbye(){this.emit(":tell",goodbyeMessage)}var newSessionHandler={LaunchRequest:welcome,"AMAZON.HelpIntent":help,Unhandled:startOver},startGameHandlers=Alexa.CreateStateHandler(states.STARTMODE,{"AMAZON.YesIntent":function(){visited=[nodes.length];var a=helper.debugFunction_walkNode(START_NODE);a===!0&&this.emit(":tell",loopsDetectedMessage),this.handler.state=states.ASKMODE;var b=helper.getSpeechForNode(START_NODE);this.attributes.currentNode=START_NODE,this.emit(":ask",b,b)},"AMAZON.NoIntent":goodbye,"AMAZON.StopIntent":goodbye,"AMAZON.CancelIntent":goodbye,"AMAZON.HelpIntent":help,Unhandled:startOver}),askQuestionHandlers=Alexa.CreateStateHandler(states.ASKMODE,{"AMAZON.YesIntent":function(){helper.yesOrNo(this,"yes")},"AMAZON.NoIntent":function(){helper.yesOrNo(this,"no")},"AMAZON.StopIntent":goodbye,"AMAZON.CancelIntent":goodbye,"AMAZON.StartOverIntent":welcome,Unhandled:function(){this.emit(":ask",promptToSayYesNo,promptToSayYesNo)}}),descriptionHandlers=Alexa.CreateStateHandler(states.DESCRIPTIONMODE,{"AMAZON.YesIntent":welcome,"AMAZON.NoIntent":goodbye,"AMAZON.StopIntent":goodbye,"AMAZON.CancelIntent":goodbye,"AMAZON.StartOverIntent":welcome,DescriptionIntent:function(){helper.giveDescription(this)},Unhandled:function(){this.emit(":ask",promptToSayYesNo,promptToSayYesNo)}});

alexa-sdk-machina-refactored.js

// Converted refactored code snippet from alexa-sdk-fsm-refactored.js into machina style FSM notation
const machina = require('machina');

var myMachina = machina.Fsm.extend( {

    initialState: "uninitialized",

    states: {
        uninitialized: { // set state to start up and  welcome the user
            // State used to mimic alexa-sdk newSession handler for alexa-app (which lacks newSession handlers)
            launch: "WELCOME",
            AMAZON_HelpIntent: "HELP",
            "*": "STARTOVER"
        },
        WELCOME: { // User invoked the skill or game restarted
            _onEnter: function () {
                // reset the game state to start mode
                this.handler.state = states.STARTMODE;
                this.emit(':ask', welcomeMessage, repeatWelcomeMessage);
            }
        },
        HELP: { // User is prompted to say yes or no
            _onEnter: function () {
                this.handler.state = states.STARTMODE;
                this.emit(':ask', helpMessage, helpMessage);
            }
        },
        STARTOVER: { // User is prompted to say yes or no
            _onEnter: function () {
                this.handler.state = states.STARTMODE;
                this.emit(':ask', promptToStartMessage, promptToStartMessage);
            }
        },

// --------------- Functions that control the skill's behavior -----------------------

        STARTMODE: { // Called at the start of the game, picks and asks first question for the user
            AMAZON_YesIntent: function () {

                // ---------------------------------------------------------------
                // check to see if there are any loops in the node tree - this section can be removed in production code
                visited = [nodes.length];
                var loopFound = helper.debugFunction_walkNode(START_NODE);
                if( loopFound === true)
                {
                    // comment out this line if you know that there are no loops in your decision tree
                    this.emit(':tell', loopsDetectedMessage);
                }
                // ---------------------------------------------------------------

                // set state to asking questions
                this.handler.state = states.ASKMODE;

                // ask first question, the response will be handled in the askQuestionHandler
                var message = helper.getSpeechForNode(START_NODE);

                // record the node we are on
                this.attributes.currentNode = START_NODE;

                // ask the first question
                this.emit(':ask', message, message);
            },
            AMAZON_NoIntent: "GOODBYE",
            AMAZON_StopIntent: "GOODBYE",
            AMAZON_CancelIntent: "GOODBYE",
            AMAZON_HelpIntent: "HELP",
            "*": "STARTOVER"
        },

// user will have been asked a question when this intent is called. We want to look at their yes/no
// response and then ask another question. If we have asked more than the requested number of questions Alexa will
// make a choice, inform the user and then ask if they want to play again
        ASKMODE: { // Alexa is asking user the questions.
            AMAZON_YesIntent: function () {
                // Handle Yes intent.
                helper.yesOrNo(this,'yes');
            },
            AMAZON_NoIntent: function () {
                // Handle No intent.
                helper.yesOrNo(this, 'no');
            },
            AMAZON_StopIntent: "GOODBYE",
            AMAZON_CancelIntent: "GOODBYE",
            AMAZON_StartOverIntent: "WELCOME",
            "*": function () {
                this.emit(':ask', promptToSayYesNo, promptToSayYesNo);
            }
        },

// user has heard the final choice and has been asked if they want to hear the description or to play again
        DESCRIPTIONMODE: { // Alexa is describing the final choice and prompting to start again or quit
            AMAZON_YesIntent: "WELCOME",
            AMAZON_NoIntent: "GOODBYE",
            AMAZON_StopIntent: "GOODBYE",
            AMAZON_CancelIntent: "GOODBYE",
            AMAZON_StartOverIntent: "WELCOME",
            DescriptionIntent: function () {
                //var reply = this.event.request.intent.slots.Description.value;
                //console.log('HEARD: ' + reply);
                helper.giveDescription(this);
            },
            "*": function () {
                this.emit(':ask', promptToSayYesNo, promptToSayYesNo);
            }
        },
        GOODBYE: { // User decided to quick the game
            _onEnter: function () {
                this.emit(':tell', goodbyeMessage);
            }
        },
    }
} );

alexa-sdk-machina-refactored.min.js

const machina=require("machina");var myMachina=machina.Fsm.extend({initialState:"uninitialized",states:{uninitialized:{launch:"WELCOME",AMAZON_HelpIntent:"HELP","*":"STARTOVER"},WELCOME:{_onEnter:function(){this.handler.state=states.STARTMODE,this.emit(":ask",welcomeMessage,repeatWelcomeMessage)}},HELP:{_onEnter:function(){this.handler.state=states.STARTMODE,this.emit(":ask",helpMessage,helpMessage)}},STARTOVER:{_onEnter:function(){this.handler.state=states.STARTMODE,this.emit(":ask",promptToStartMessage,promptToStartMessage)}},STARTMODE:{AMAZON_YesIntent:function(){visited=[nodes.length];var a=helper.debugFunction_walkNode(START_NODE);a===!0&&this.emit(":tell",loopsDetectedMessage),this.handler.state=states.ASKMODE;var b=helper.getSpeechForNode(START_NODE);this.attributes.currentNode=START_NODE,this.emit(":ask",b,b)},AMAZON_NoIntent:"GOODBYE",AMAZON_StopIntent:"GOODBYE",AMAZON_CancelIntent:"GOODBYE",AMAZON_HelpIntent:"HELP","*":"STARTOVER"},ASKMODE:{AMAZON_YesIntent:function(){helper.yesOrNo(this,"yes")},AMAZON_NoIntent:function(){helper.yesOrNo(this,"no")},AMAZON_StopIntent:"GOODBYE",AMAZON_CancelIntent:"GOODBYE",AMAZON_StartOverIntent:"WELCOME","*":function(){this.emit(":ask",promptToSayYesNo,promptToSayYesNo)}},DESCRIPTIONMODE:{AMAZON_YesIntent:"WELCOME",AMAZON_NoIntent:"GOODBYE",AMAZON_StopIntent:"GOODBYE",AMAZON_CancelIntent:"GOODBYE",AMAZON_StartOverIntent:"WELCOME",DescriptionIntent:function(){helper.giveDescription(this)},"*":function(){this.emit(":ask",promptToSayYesNo,promptToSayYesNo)}},GOODBYE:{_onEnter:function(){this.emit(":tell",goodbyeMessage)}}}});