background-service-worker.js

//
// Message listener
//

const MAX_RETRY_DURATION = 500 // 500 ms
const RETRY_DELAY = 50 // 50 ms

//
// Message listener
//

chrome.runtime.onMessage.addListener((message, sender, reply) => {
  if (message.type === 'mute_other_streams') {
    // Mute all Twitch tabs except the one that sent the message.
    //
    // NOTE: If the user changes tab using his keyboard, `chrome.tabs.query()` will work on the first call, but if he
    // uses his mouse `query()` will return an error. In this case, we'll retry every RETRY_DELAY until it works or
    // abort after MAX_RETRY_DURATION.

    muteOtherTwitchTabs(sender.tab, 0)
  }
})

//
// Functions
//

function muteOtherTwitchTabs(currentTab, timeElapsedSinceFirstTry) {
  chrome.tabs.query({ url: 'https://*.twitch.tv/*' }).then(
    tabs => onQueryTabsSuccess(tabs, currentTab),
    err => onQueryTabsError(err, currentTab, timeElapsedSinceFirstTry)
  )
}

function onQueryTabsError(err, currentTab, timeElapsedSinceFirstTry) {
  // If less than 1 sec has elapsed since the content script sent the command, retry after a small delay
  if (timeElapsedSinceFirstTry < MAX_RETRY_DURATION) {
    setTimeout(() => muteOtherTwitchTabs(currentTab, timeElapsedSinceFirstTry + RETRY_DELAY), RETRY_DELAY)
    return
  }
  // Otherwise abort and log the error
  else {
    console.error(chrome.runtime.lastError.message)
    return
  }
}

function onQueryTabsSuccess(twitchTabs, currentTab) {
  twitchTabs.forEach(tab => chrome.tabs.update(tab.id, {
    muted: tab.id !== currentTab.id
  }))
}