I am trying to use turn.js to make a couple of audio flipbooks. In this case I have a single mp3 audio file and I want to play it starting from a startTime until and endTime page by page for pages supporting it. I am able to stop to play the audio after an interval but I did not find a solution to start to play the audio from a startTime > of 0 seconds.
This is my code:

let currentPage = 0; // Initialize the current page variable
let audio = null; // Initialize the audio variable

const DEBUG_MODE = true; 

function debugLog(...args) {
    if (DEBUG_MODE) {
        console.log(...args);
    }
}

function loadApp() {
    var flipbook = $('.flipbook');
    var audio = new Audio();

    function playAudio(audioFile, startTime, endTime) {
      stopAudio(); // Stop any currently playing audio
      const audio = new Audio(audioFile);
      let startTimeSet = false; // Flag variable to keep track of whether startTime has been set

      // Debugging logs
      debugLog(`Loading audio file: ${audioFile}`);
      debugLog(`Start time: ${startTime}, End time: ${endTime}`);

      audio.addEventListener('loadeddata', () => {
        if (!startTimeSet) { // Only set startTime if it hasn't been set already
          audio.currentTime = startTime;
          debugLog(`Audio data loaded. Setting start time to: ${audio.currentTime}`);
          startTimeSet = true; // Set the flag variable to true
        }
        audio.play();
      });

      audio.addEventListener('timeupdate', function() {
        if (audio.currentTime >= endTime) {
          stopAudio();
          debugLog('Audio stopped automatically at the end time.');
        }
      });

      audio.addEventListener('error', function(e) {
        debugLog('Error during audio playback:', e);
      });

      audio.load(); // Load the audio file
      debugLog('Audio loaded.');
    }

    function stopAudio() {
        if (window.currentAudio) {
            window.currentAudio.pause();
            window.currentAudio = null;
        }
    }
    
    function stopTTS() {
        window.speechSynthesis.cancel();
    }

    function playTTS(text, lang) {
        stopTTS();
        const utterance = new SpeechSynthesisUtterance(text);
        utterance.lang = lang;
        window.speechSynthesis.speak(utterance);
    }
    
    function handlePageTurned(data, page) {
        var pageIndex = page - 1; // Adjust for 0-based index

        if (pageIndex < 0 || pageIndex >= data.pages.length) {
            return;
        }
        var currentPage = data.pages[pageIndex];
        var combinedAudio = currentPage.audio;
        var combinedText = currentPage.text;
        var combinedLang = currentPage.lang || navigator.language || 'it-IT';
        debugLog('currentPage:', currentPage);
        debugLog('currentPage.image:', currentPage.image);
        debugLog('combinedAudio:', combinedAudio);
        debugLog('currentPage.start_time:', currentPage.start_time);
        debugLog('currentPage.end_time:', currentPage.end_time);
        debugLog('combinedText:', combinedText);
        debugLog('combinedLang:', combinedLang);

        if (combinedAudio) {
            playAudio(combinedAudio, currentPage.start_time, currentPage.end_time);
        } else if (combinedText) {
            playTTS(combinedText, combinedLang);
        }
    }
    
    // Check if the CSS was already loaded
    if (flipbook.width() == 0 || flipbook.height() == 0) {
        setTimeout(loadApp, 10);
        return;
    }

    // Fetch the JSON file
    fetch('flipbook.json')
        .then(response => response.json())
        .then(data => {
            debugLog('JSON data loaded:', data); // Debug: verifica i dati JSON caricati
            // Loop through the pages in the JSON data
            data.pages.forEach((page, index) => {
                // Create a new page div
                var newPage = document.createElement('div');

                // Set the class based on the page type
                if( page.type === 'hard' ) {
                    newPage.className = 'hard'
                }
                else if( page.type === 'left' ) {
                    newPage.className = 'page left'
                }
                else if( page.type === 'right' ) {
                    newPage.className = 'page right'
                }
                else if( (page.type === 'double' ) && (index % 2 === 0)) {
                    newPage.className = 'page double left'
                }
                else {
                    newPage.className = 'page double right'
                }

                // Set the background image
                newPage.style.backgroundImage = `url(${page.image})`;
                // Add data attributes for audio and text-to-speech
                $(newPage).data('audio', page.audio);
                $(newPage).data('text', page.text);
                $(newPage).data('lang', page.lang);
                $(newPage).data('startTime', page.start_time);
                $(newPage).data('endTime', page.end_time);
                // Append the new page div to the flipbook
                flipbook.append(newPage);
            });

            // Apply the scissor effect to the soft pages
            $('.flipbook .double').scissor();

            // Create the flipbook
            $('.flipbook').turn({
                elevation: 50,
                gradients: true,
                autoCenter: true,
                display: 'double', // Keep this as 'double' to maintain the original behavior for soft pages
                pages: data.pages.length, // Set the total number of pages in the flipbook
                when: {
                    turning: function(event, page, view) {
                        // Stop any current audio or TTS
                        stopAudio();
                        stopTTS();

                        // Ensure hard pages turn as single pages
                        if ($('.flipbook .page-wrapper').eq(page - 1).hasClass('hard')) {
                            $('.flipbook').turn('display', 'single');
                        } else if ($('.flipbook .page-wrapper').eq(page - 1).hasClass('double') && !$('.flipbook').turn('animating')) {
                            $('.flipbook').turn('display', 'double');
                        }
                        debugLog('Turning to page:', page); // Debug: verifica il numero di pagina che sta girando
                    },
                    turned: function(event, page, view) {
                        handlePageTurned(data, page);
                    }
                }
            });
        })
        .catch(error => console.error('Error:', error));
}

// Load the HTML4 version if there's not CSS transform
yepnope({
    test: Modernizr.csstransforms,
    yep: ['../../lib/turn.min.js'],
    nope: ['../../lib/turn.html4.min.js'],
    both: ['../../lib/scissor.min.js', 'css/double-page-hard.css'],
    complete: loadApp
});

Every solution/suggestion is very welcome.