theme.onUpdated
Fires when a theme supplied as a browser extension is applied or removed. Specifically:
- when a static theme is installed
- when a dynamic theme calls theme.update()ortheme.reset()
- when a theme gets uninstalled.
Note that this event is not fired for changes to the built-in themes.
Syntax
js
browser.theme.onUpdated.addListener(listener)
browser.theme.onUpdated.removeListener(listener)
browser.theme.onUpdated.hasListener(listener)
Events have three functions:
- addListener(listener)
- 
    Adds a listener to this event. 
- removeListener(listener)
- 
    Stop listening to this event. The listenerargument is the listener to remove.
- hasListener(listener)
- 
    Check whether listeneris registered for this event. Returnstrueif it is listening,falseotherwise.
addListener syntax
Parameters
- listener
- 
    The function called when this event occurs. The function is passed these arguments: - updateInfo
- 
        object. An object containing two properties:- theme
- 
            object. If the event fired because an extension-supplied theme was removed, this will be an empty object. If it fired because an extension-supplied theme was applied, then it will be atheme.Themeobject representing the theme that was applied.
- windowIdOptional
- 
            integer. The ID of the window for which theme has been updated. If this property is not present, it means that the theme was updated globally.
 
 
Browser compatibility
BCD tables only load in the browser
Examples
js
function handleUpdated(updateInfo) {
  if (updateInfo.theme.colors) {
    console.log(`Theme was applied: ${updateInfo.theme}`);
  } else {
    console.log(`Theme was removed`);
  }
}
browser.theme.onUpdated.addListener(handleUpdated);