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() or theme.reset()
• when a theme gets uninstalled.

Note that this event is not fired for changes to the built-in themes.

Syntax

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 listener argument is the listener to remove.

hasListener(listener)

Check whether listener is registered for this event. Returns true if it is listening, false otherwise.

addListener syntax

Parameters

callback

Function that will be called when this event occurs. The function will be passed the following 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 a theme.Theme object 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

Examples

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);

Example extensions

• theme-integrated-sidebar