clipboard-pronouncer.user.js

// ==UserScript==
// @name         Clipboard pronouncer
// @namespace    https://houkanshan.com
// @version      0.1
// @description  try to take over the world!
// @author       Houkanshan
// @include      http://*/*
// @include      https:/*/*
// @exclude      https://docs.google.com/spreadsheets*
// @grant        none
// ==/UserScript==

var utterances = []; // Chrome Bug: https://stackoverflow.com/a/35935851
var currMsg = null;

function read(text) {
    return new Promise((resolve, reject) => {
        window.speechSynthesis.cancel();
        var msg = new SpeechSynthesisUtterance(text);
        utterances.push(msg);
        msg.addEventListener('end', () => {
            if (msg._stop) { return reject(); }
            resolve();
        });
        currMsg = msg;
        window.speechSynthesis.speak(msg);
    });
}

(function() {
    'use strict';
    if (location.href.indexOf('https://https://docs.google.com/spreadsheets') === 0) { return; } // exclude doesn't work..
    document.addEventListener('copy', function(e) {
        if (currMsg) {
            currMsg._stop = true;
            currMsg = null;
        }
        utterances = [];
        var text = window.getSelection().toString();
        text.split(/\n+/).reduce((acc, word) => {
            return acc.then(() => read(word));
        }, Promise.resolve()).then(() => utterances = [], () => {});
    });

})();