Callbacks

There are a number of Javascript callbacks that you can access in order to respond to system events and react accordingly.

📘
Recommend Using in the Playlist HTML Overlay
These callbacks are usually more useful when implementing code within an HTML overlay vs a Webapp.

Callback	Description	Returns
onApiStatusChange	Called when the API Status changes. You can use this to react to the device going online or offline.	The current `status` string
onPageChange	Called when the Playlist transitions to a new page. Useful for overrides and responding to different pages.	The current `page` object
onPlaylistChange	Called when the Playlist is updated, typically when playlist name or id is changed.	The current `playlist` object
onGeoChange	Called when the geographic coordinates of the device change. You'll need a device and a Player that supports forwarding geographic coordinates such as our Android Player running on an Android tablet.	The current `coordinates` object
onOverrideStart	Called when an Override starts	The starting `override` object
onOverrideEnd	Called when an Override ends	The ending `override` object
onSerialMessage	Called when a message is received (a string) from the configured serial port on the device	The `message` string
onPageDuration	called when page start or page duration changes. Only works for: page with a fixed "duration" set page without a "duration" but there's a video (E.g. YouTube) that would cause the playlist to advance.	The number 'float'

Example of callbacks usage:

window.onloadTelemetryTV = function (ttv) {
  ttv.onApiStatusChange(function (status) {
    console.log(`API Status change to: ${status}`);
  });

  ttv.onPageChange(function (page) {
    console.log(`Current Page: ${page.name} (${page.id})`);
  });

  ttv.onPlaylistChange(function (playlist) {
    console.log(`Current Playlist: ${playlist.name} (${playlist.id})`);
  });

  ttv.onGeoChange(function (coordinates) {
    console.log('My oordinates are now:', coordinates);
  });

  ttv.onOverrideStart(function (override) {
    console.log(`Override started: ${override.name} (${override.id})`);
  });

  ttv.onOverrideEnd(function (override) {
    console.log(`Override ended: ${override.name} (${override.id})`);
  });

  ttv.onSerialMessage(function (message) {
    console.log('Serial Message received:', message);
  });
  
  ttv.onPageDuration((cb) => {
    window.console.log('Length of video', cb)
  })
};