storage.onChanged
Fired when one or more items change.
Syntax
browser.storage.onChanged.addListener(callback)
browser.storage.onChanged.removeListener(listener)
browser.storage.onChanged.hasListener(listener)
Events have three functions:
addListener(callback)
-
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. Returnstrue
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:
changes
-
object
. Object describing the change. This contains one property for each key that changed. The name of the property is the name of the key that changed, and its value is astorage.StorageChange
object describing the change to that item. areaName
-
string
. The name of the storage area ("sync"
,"local"
, or"managed"
) to which the changes were made.
Browser compatibility
BCD tables only load in the browser
Examples
/*
Log the storage area that changed,
then for each item changed,
log its old value and its new value.
*/
function logStorageChange(changes, area) {
console.log("Change in storage area: " + area);
let changedItems = Object.keys(changes);
for (let item of changedItems) {
console.log(item + " has changed:");
console.log("Old value: ");
console.log(changes[item].oldValue);
console.log("New value: ");
console.log(changes[item].newValue);
}
}
browser.storage.onChanged.addListener(logStorageChange);
Example extensions
Note: This API is based on Chromium's chrome.storage
API. This documentation is derived from storage.json
in the Chromium code.
Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.