Linux pacmd (PulseAudio) output device sink toggler script

sound-switcher.js

#!/usr/bin/node

// You will need node.js installed to run this!
// Invoke this script to toggle between the two configured devices

// Make sure the following is configured in /etc/pulse/default.pa:
// load-module module-stream-restore restore_device=false

// Configure the two devices to toggle between here
// Use "pacmd list-sinks" to find device names to use here, the script won't work if you don't!
const myDevices = [
    'alsa_output.pci-0000_0a_00.4.analog-stereo', // Headphones
    'alsa_output.pci-0000_08_00.1.hdmi-stereo-extra4', // Speakers
]

const { promisify } = require('util');
const exec = promisify(require('child_process').exec)

const activeSinkRegex = /\* index: .+\n.*name: <(.+?)>/
const sinkInputsRegex = /index: ([0-9]+)/g
const rawSinksP = exec('pacmd list-sinks')
const rawSinkInputsP = exec('pacmd list-sink-inputs')

const setNewDevice = async deviceIndex => {
    // Set the given index as the default audio sink
    const changeDefaultP = exec(`pacmd set-default-sink ${deviceIndex}`)

    const { stdout: rawSinkInputs } = await rawSinkInputsP
    const sinkInputIndices = [...(rawSinkInputs.matchAll(sinkInputsRegex))].map(_ => _[1])

    await changeDefaultP
    return Promise.all(sinkInputIndices.map(
        // Move each Sink input to the new default sink
        inputIndex => exec(`pacmd move-sink-input ${inputIndex} ${deviceIndex}`)
    ))
}

const currentDeviceP = rawSinksP.then(
    ({ stdout: rawSinks }) => rawSinks.match(activeSinkRegex)[1]
)

const newDeviceIndexP = currentDeviceP.then(
    // Get device name
    currentDevice => myDevices.find(device => device !== currentDevice)
).then(newDeviceName => rawSinksP.then(({ stdout: rawSinks }) => {
    // Find and return the index for the new device name
    const newDeviceRegex = new RegExp(`index: ([0-9]+)\n.*name: <${newDeviceName}>`)
    return rawSinks.match(newDeviceRegex)[1]
}))

newDeviceIndexP.then(setNewDevice)
newDeviceIndexP.then(newSinkIndex => console.log(`Switching to sink with index ${newSinkIndex}...`))