Google cloud text to speech API

When using the Google Cloud Text-to-Speech API, the default behavior of the synthesizeSpeech() method, as described in the synthesizeSpeech() documentation, is to return the audioContent as a complete buffer.

However, if you want to enable streaming playback for long audios, you can convert the buffer to a file streaming response. To achieve this, you can utilize the PassThrough class from the Node.js Stream API, as outlined in the PassThrough documentation.

Here is a sample snippet from a Nuxt 3 project that demonstrates this:

import { TextToSpeechClient } from "@google-cloud/text-to-speech/build/src/v1";

// ...

const request = {
  input: { text },
  voice: { languageCode: language, ssmlGender: "NEUTRAL" },
  audioConfig: { audioEncoding: "OGG_OPUS" },
const [response] = await client.synthesizeSpeech(request);
// response.audioContent is a Buffer object
if (!response.audioContent) return { error: "No audio content" };

// PassThrough is both a write and read stream
const bufferStream = new PassThrough();
// set the whole buffer content as PassThrough input.

// set mime types
setHeader(event, 'content-type', 'audio/ogg; codecs=opus');

// send the PassThrough output as HTTP streamed response
return sendStream(event, bufferStream);