Speech Synthesizer behavior change in V4

[alokraj68]

Version

4.6 vis CDN

Describe the bug

In V3, we had an option to stop the speech from code and after that, the speech synthesizes won't work until the user again uses speech recognizer.

In V4, this behavior has changed. The bot speaks out every message even after stoping it from code.

To Reproduce

Steps to reproduce the behavior:

1. Go to any voice-enabled samples.
2. Click on mic
3. Speak something to the bot and wait for the bot to speak back.
4. Execute the code segment
   speechServicesPonyfill.speechSynthesis.queue.stop(); speechServicesPonyfill.speechSynthesis.cancel();
   The speech will stop now.
5. Now type something to the bot. The reply will be again spoken by the bot.

Expected behavior

The bot should not speak once this code segment is executed. This was the behavior in V3.

Additional context

This is an upgrade issue and the context is that if we minimize the bot and we trigger any message from the user to the bot via piggybacking, the reply will be spoken by the bot even when it is minimized.

[Bug]

[alokraj68]

@corinagum, Can you please follow these steps and help me out resolve this?

[compulim]

1. The API of speechServicesPonyfill.speechSynthesis conforms to Web Speech API spec. Since the speechSynthesis.queue is not specified in the spec, calling queue.stop is not a supported feature and intended to change from time to time
2. In Web Chat, instead of using SpeechSynthesis to control the queue (e.g. stop/suspend/resume synthesis), we build our own queue for controlling how utterance are being synthesized
   • This is because the spec lack of a way to cancel/dequeue a single utterance, which Web Chat requires
   • As you may explored into this area already, the SpeechSynthesis object only support cancelling all utterances, but not a single one
3. If you would want to control the queue, today, you can create a custom store and dispatch few actions to it
   • Dispatching WEB_CHAT/STOP_SPEAKING will stop Web Chat from synthesizing the current and upcoming activities
     • This feature may change when we implement Design: Switching input mode #2211 in our R8 release, which is currently planned for Spring 2020
     • In R8, both the dev and the user will have better control on how/when to synthesize an activity