Fix System TTS ending abruptly in Chrome on Windows

public/scripts/extensions/tts/system.js

@@ -1,5 +1,74 @@
 export { SystemTtsProvider }
 
+/**
+ * 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.lang = utt.lang;
+        newUtt.voice = utt.voice;
+        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);
+};
+
 class SystemTtsProvider {
     //########//
     // Config //
@@ -142,7 +211,12 @@ class SystemTtsProvider {
             utterance.pitch = this.settings.pitch || 1;
             utterance.onend = () => resolve(silence);
             utterance.onerror = () => reject();
-            speechSynthesis.speak(utterance);
+            speechUtteranceChunker(utterance, {
+                chunkLength: 200,
+            }, function () {
+                //some code to execute when done
+                console.log('System TTS done');
+            });
         });
     }
 }