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@hsed hsed/chunkify.js forked from woollsta/chunkify.js
Created Mar 18, 2017

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Fixes an issue with Google Chrome Speech Synthesis where long texts pause mid-speaking. The function takes in a speechUtterance object and intelligently chunks it into smaller blocks of text that are stringed together one after the other. Basically, you can play any length of text. See http://stackoverflow.com/questions/21947730/chrome-speech-sy…
/**
* Chunkify
* Google Chrome Speech Synthesis Chunking Pattern
* Fixes inconsistencies with speaking long texts in speechUtterance objects
* Licensed under the MIT License
*
* Peter Woolley and Brett Zamir
* Modified by Haaris for bug fixes
*/
var speechUtteranceChunker = function (utt, settings, callback) {
settings = settings || {};
var newUtt;
var txt = (settings && settings.offset !== undefined ? utt.text.substring(settings.offset) : utt.text);
if (utt.voice && utt.voice.voiceURI === 'native') { // Not part of the spec
newUtt = utt;
newUtt.text = txt;
newUtt.addEventListener('end', function () {
if (speechUtteranceChunker.cancel) {
speechUtteranceChunker.cancel = false;
}
if (callback !== undefined) {
callback();
}
});
}
else {
var chunkLength = (settings && settings.chunkLength) || 160;
var pattRegex = new RegExp('^[\\s\\S]{' + Math.floor(chunkLength / 2) + ',' + chunkLength + '}[.!?,]{1}|^[\\s\\S]{1,' + chunkLength + '}$|^[\\s\\S]{1,' + chunkLength + '} ');
var chunkArr = txt.match(pattRegex);
if (chunkArr == null || chunkArr[0] === undefined || chunkArr[0].length <= 2) {
//call once all text has been spoken...
if (callback !== undefined) {
callback();
}
return;
}
var chunk = chunkArr[0];
newUtt = new SpeechSynthesisUtterance(chunk);
var x;
for (x in utt) {
if (utt.hasOwnProperty(x) && x !== 'text') {
newUtt[x] = utt[x];
}
}
newUtt.addEventListener('end', function () {
if (speechUtteranceChunker.cancel) {
speechUtteranceChunker.cancel = false;
return;
}
settings.offset = settings.offset || 0;
settings.offset += chunk.length;
speechUtteranceChunker(utt, settings, callback);
});
}
if (settings.modifier) {
settings.modifier(newUtt);
}
console.log(newUtt); //IMPORTANT!! Do not remove: Logging the object out fixes some onend firing issues.
//placing the speak invocation inside a callback fixes ordering and onend issues.
setTimeout(function () {
speechSynthesis.speak(newUtt);
}, 0);
};
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