The lambda code to the Guitar Tuner skill we are building

guitar-tuner.js

/* This code has been generated from your interaction model

/* eslint-disable  func-names */
/* eslint quote-props: ["error", "consistent"]*/

// There are three sections, Text Strings, Skill Code, and Helper Function(s).
// You can copy and paste the contents as the code for a new Lambda function, using the alexa-skill-kit-sdk-factskill template.
// This code includes helper functions for compatibility with versions of the SDK prior to 1.0.9, which includes the dialog directives.



 // 1. Text strings =====================================================================================================
 //    Modify these strings and messages to change the behavior of your Lambda function


var speechOutput;
var reprompt;
var welcomeOutput = "Welcome to Guitar Tuner. You can ask me to play a note, like a low E, or a chord. How can I help?";
var welcomeReprompt = "You can say something like: give me a low E, or play the D string.";
 // 2. Skill Code =======================================================================================================
"use strict";
var Alexa = require('alexa-sdk');
var APP_ID = undefined;  // TODO replace with your app ID (OPTIONAL).
var speechOutput = '';
var handlers = {
    'LaunchRequest': function () {
        this.emit(':ask', welcomeOutput, welcomeReprompt);
    },
	'AMAZON.HelpIntent': function () {
        speechOutput = '';
        reprompt = '';
        this.emit(':ask', speechOutput, reprompt);
    },
    'AMAZON.CancelIntent': function () {
        speechOutput = '';
        this.emit(':tell', speechOutput);
    },
    'AMAZON.StopIntent': function () {
        speechOutput = '';
        this.emit(':tell', speechOutput);
    },
    'SessionEndedRequest': function () {
        speechOutput = '';
        this.emit(':saveState', true);//uncomment to save attributes to db on session end
        this.emit(':tell', speechOutput);
    },
	"PlayNoteIntent": function () {
		var speechOutput = '';
    var speechReprompt = '';
        
		var noteSlot = resolveCanonical(this.event.request.intent.slots.note);
		console.log('User requested note: ' + noteSlot);

		var pitchSlot = resolveCanonical(this.event.request.intent.slots.pitch);
		console.log('User requests pitch: ' + pitchSlot);
		
		var notes = {
		    'a' : {
		        'low' : 'https://URL-to-your-bucket/a.mp3',
		        'high': 'https://URL-to-your-bucket/a.mp3'
		    },
		    'b' : {
		        'low' : 'https://URL-to-your-bucket/b.mp3',
		        'high': 'https://URL-to-your-bucket/b.mp3'
		    },
		    'd' : {
		        'low' : 'https://URL-to-your-bucket/d.mp3',
		        'high': 'https://URL-to-your-bucket/d.mp3'
		    },
		    'e' : {
		        'low' : 'https://URL-to-your-bucket/e_low.mp3',
		        'high': 'https://URL-to-your-bucket/e_high.mp3'
		    },
		    'g' : {
		        'low' : 'https://URL-to-your-bucket/g.mp3',
		        'high': 'https://URL-to-your-bucket/g.mp3'
		    }
		}

        var pitches = [
            'low',
            'high'
        ];
        
        var note = '';
        var pitch = '';
                
        if(!noteSlot) {
            this.emit(':ask', 'I did not hear a note. Which note do you want to hear?', 'You can say something like play me an E')
        } else {
            note = noteSlot.toLowerCase();
            this.attributes['note'] = note;
        }
        
        if(pitchSlot) {
            pitch = pitchSlot.toLowerCase();
        }

        
        if(notes[note]) {
            var audio = '';
            
            if(pitchSlot && pitches.indexOf(pitchSlot) > -1) {
                pitch = pitchSlot;    
            } else {
                pitch = 'low';
            }
            
            var audioSrc = notes[note][pitch];
            
            speechOutput = 'Here is your note: <audio src="' + audioSrc + '" />';
            speechReprompt = 'Would you like to hear it again?';
            
        } else {
            speechOutput = 'Sorry, the note you asked for is not supported yet.'
            speechReprompt = 'I support: A, B, D, low E, high E, and G';
        }
        
        this.emit(":tell", speechOutput);
    },	
	'Unhandled': function () {
        speechOutput = "The skill didn't quite understand what you wanted.  Do you want to try something else?";
        this.emit(':ask', speechOutput, speechOutput);
    }
};

exports.handler = (event, context) => {
    var alexa = Alexa.handler(event, context);
    alexa.APP_ID = APP_ID;
    // To enable string internationalization (i18n) features, set a resources object.
    //alexa.resources = languageStrings;
    alexa.registerHandlers(handlers);
	alexa.dynamoDBTableName = 'guitar-tuner'; //uncomment this line to save attributes to DB
    alexa.execute();
};

//    END of Intent Handlers {} ========================================================================================
// 3. Helper Function  =================================================================================================

function resolveCanonical(slot){
	//this function looks at the entity resolution part of request and returns the slot value if a synonyms is provided
    try{
		var canonical = slot.resolutions.resolutionsPerAuthority[0].values[0].value.name;
	}catch(err){
	    console.log(err.message);
	    var canonical = slot.value;
	};
	return canonical;
};

function delegateSlotCollection(){
  console.log("in delegateSlotCollection");
  console.log("current dialogState: "+this.event.request.dialogState);
    if (this.event.request.dialogState === "STARTED") {
      console.log("in Beginning");
	  var updatedIntent= null;
	  // updatedIntent=this.event.request.intent;
      //optionally pre-fill slots: update the intent object with slot values for which
      //you have defaults, then return Dialog.Delegate with this updated intent
      // in the updatedIntent property
      //this.emit(":delegate", updatedIntent); //uncomment this is using ASK SDK 1.0.9 or newer
	  
	  //this code is necessary if using ASK SDK versions prior to 1.0.9 
	  if(this.isOverridden()) {
			return;
		}
		this.handler.response = buildSpeechletResponse({
			sessionAttributes: this.attributes,
			directives: getDialogDirectives('Dialog.Delegate', updatedIntent, null),
			shouldEndSession: false
		});
		this.emit(':responseReady', updatedIntent);
		
    } else if (this.event.request.dialogState !== "COMPLETED") {
      console.log("in not completed");
      // return a Dialog.Delegate directive with no updatedIntent property.
      //this.emit(":delegate"); //uncomment this is using ASK SDK 1.0.9 or newer
	  
	  //this code necessary is using ASK SDK versions prior to 1.0.9
		if(this.isOverridden()) {
			return;
		}
		this.handler.response = buildSpeechletResponse({
			sessionAttributes: this.attributes,
			directives: getDialogDirectives('Dialog.Delegate', updatedIntent, null),
			shouldEndSession: false
		});
		this.emit(':responseReady');
		
    } else {
      console.log("in completed");
      console.log("returning: "+ JSON.stringify(this.event.request.intent));
      // Dialog is now complete and all required slots should be filled,
      // so call your normal intent handler.
      return this.event.request.intent;
    }
}


function randomPhrase(array) {
    // the argument is an array [] of words or phrases
    var i = 0;
    i = Math.floor(Math.random() * array.length);
    return(array[i]);
}
function isSlotValid(request, slotName){
        var slot = request.intent.slots[slotName];
        //console.log("request = "+JSON.stringify(request)); //uncomment if you want to see the request
        var slotValue;

        //if we have a slot, get the text and store it into speechOutput
        if (slot && slot.value) {
            //we have a value in the slot
            slotValue = slot.value.toLowerCase();
            return slotValue;
        } else {
            //we didn't get a value in the slot.
            return false;
        }
}

//These functions are here to allow dialog directives to work with SDK versions prior to 1.0.9
//will be removed once Lambda templates are updated with the latest SDK

function createSpeechObject(optionsParam) {
    if (optionsParam && optionsParam.type === 'SSML') {
        return {
            type: optionsParam.type,
            ssml: optionsParam['speech']
        };
    } else {
        return {
            type: optionsParam.type || 'PlainText',
            text: optionsParam['speech'] || optionsParam
        };
    }
}

function buildSpeechletResponse(options) {
    var alexaResponse = {
        shouldEndSession: options.shouldEndSession
    };

    if (options.output) {
        alexaResponse.outputSpeech = createSpeechObject(options.output);
    }

    if (options.reprompt) {
        alexaResponse.reprompt = {
            outputSpeech: createSpeechObject(options.reprompt)
        };
    }

    if (options.directives) {
        alexaResponse.directives = options.directives;
    }

    if (options.cardTitle && options.cardContent) {
        alexaResponse.card = {
            type: 'Simple',
            title: options.cardTitle,
            content: options.cardContent
        };

        if(options.cardImage && (options.cardImage.smallImageUrl || options.cardImage.largeImageUrl)) {
            alexaResponse.card.type = 'Standard';
            alexaResponse.card['image'] = {};

            delete alexaResponse.card.content;
            alexaResponse.card.text = options.cardContent;

            if(options.cardImage.smallImageUrl) {
                alexaResponse.card.image['smallImageUrl'] = options.cardImage.smallImageUrl;
            }

            if(options.cardImage.largeImageUrl) {
                alexaResponse.card.image['largeImageUrl'] = options.cardImage.largeImageUrl;
            }
        }
    } else if (options.cardType === 'LinkAccount') {
        alexaResponse.card = {
            type: 'LinkAccount'
        };
    } else if (options.cardType === 'AskForPermissionsConsent') {
        alexaResponse.card = {
            type: 'AskForPermissionsConsent',
            permissions: options.permissions
        };
    }

    var returnResult = {
        version: '1.0',
        response: alexaResponse
    };

    if (options.sessionAttributes) {
        returnResult.sessionAttributes = options.sessionAttributes;
    }
    return returnResult;
}

function getDialogDirectives(dialogType, updatedIntent, slotName) {
    let directive = {
        type: dialogType
    };

    if (dialogType === 'Dialog.ElicitSlot') {
        directive.slotToElicit = slotName;
    } else if (dialogType === 'Dialog.ConfirmSlot') {
        directive.slotToConfirm = slotName;
    }

    if (updatedIntent) {
        directive.updatedIntent = updatedIntent;
    }
    return [directive];
}

How to add a yes/no intent to this code? So it can repeat the note?