User script to autoplay audio prompts on Duolingo.

duolingo-autoplay-prompts.user.js

// ==UserScript==
// @name         Duolingo Autoplay audio
// @namespace    8442918f3dbd7268b7eabd74e1ce191e
// @version      0.1
// @description  Autoplay the audio prompts on Duolingo.
// @author       Sam Saint-Pettersen <[email protected]>
// @match        https://www.duolingo.com/*
// @icon         https://s32.postimg.org/8zxj3evit/duolingo.png
// @require      http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js
// ==/UserScript==

const prefix = 'duolingo_autoplay_';
const played = prefix + 'played';
const disabled = prefix + 'disabled';
const toggler = prefix + 'toggler';

let timer = null;

let autoplay_btn = '<br><input style="margin-top: 5px; border: solid #1CAFF6 1px !important" checked="checked"';
autoplay_btn += ' id="autoplay_prompt" type="checkbox" value="1"></input>';
autoplay_btn += '<abbr style="color: #999; font-size: 9pt;"';
autoplay_btn += ' title="Audio prompts will autoplay if checked.">Autoplay?</abbr>';

function resetToggles() {
    clearInterval(timer);
    sessionStorage.setItem(played, 0);
    sessionStorage.setItem(toggler, 0);
}

function playAudioPrompt() {
    if(parseInt(sessionStorage.getItem(played)) === 0 &&
    parseInt(sessionStorage.getItem(disabled)) !== 1) {
        $('.icon-speaker-small').trigger('click');
        sessionStorage.setItem(played, 1);
    }
    if(parseInt(sessionStorage.getItem(toggler)) === 0) {
        let speaker = $('.icon-speaker-small');
        $('.icon-speaker-small').replaceWith(speaker);
        $('.icon-speaker-small').append(autoplay_btn);
        sessionStorage.setItem(toggler, 1);
    }
    setAutoplay();
    $('#autoplay_prompt').on('click', function() {
        toggleAutoplay();
    });
}

function playNextAudioPrompt() {
    resetToggles();
    timer = setTimeout(playAudioPrompt, 2500);
}

function toggleAutoplay() {
    if($('#autoplay_prompt').is(':checked')) {
        sessionStorage.setItem(disabled, 0);
    } else {
        sessionStorage.setItem(disabled, 1);
    }
}

function setAutoplay() {
    if(parseInt(sessionStorage.getItem(disabled)) === 1) {
        $('#autoplay_prompt').removeAttr('checked');
    } else {
        $('#autoplay_prompt').attr('checked', 'checked');
    }
}

(function() {
    'use strict';
    $(document).ready(function() {
        playNextAudioPrompt();
        $('#next_button').on('click', function() {
            playNextAudioPrompt();
        });
        $(document).on('keypress', function(event) {
            if(event.which === 13) {
                playNextAudioPrompt();
            }
        });
        $('a').on('click', function() {
            resetToggles();
        });
        $('button').on('click', function() {
            resetToggles();
        });
    });
})();