Browser text-to-speach

text-to-speach.js

/**
 * Uses the borwser's speech synthesis API to speak the given text. Example:
 *
 *   speak('This is a secret mission in uncharted space.', 2, 1, 2);
 *
 * @param {string} test The text to speak.
 * @param {float} rate The rate at which to speak the text, between 0.1 and 10.
 * @param {float} pitch The pitch at which to speak the text, between 0 and 2.
 * @param {int} voice The voice to use, e.g. 3.
 */
const speak = (text, rate = 1, pitch = 1, voice = 0) => {
  const textSynth = new SpeechSynthesisUtterance();

  const voices = window.speechSynthesis.getVoices();
  textSynth.voice = voices[0];
  if (voice && voice !== 0 && voices.length >= voice) {
    textSynth.voice = voices[voice];
  }

  textSynth.rate = 1;
  if (rate && rate >= 0.1 && rate <= 10) {
    textSynth.rate = rate;
  }

  textSynth.pitch = 1;
  if (pitch && pitch >= 0 && pitch <= 2) {
    textSynth.pitch = pitch;
  }

  textSynth.text = text;
  speechSynthesis.speak(textSynth);
};