StorageArea.getBytesInUse()

Gets the amount of storage space, in bytes, used one or more items being stored in the storage area.

This function only exists in browser.storage.sync
It does not exist in browser.storage.local
See https://bugzilla.mozilla.org/show_bug.cgi?id=1385832

This is an asynchronous function that returns a Promise.

Syntax

var gettingSpace = browser.storage.<storageType>.getBytesInUse(
  keys                      // null, string, or array of strings
)

<storageType> can only be storage.sync, not storage.local because of this bug.

Parameters

keys

A key (string) or keys (an array of strings) to identify the item(s) whose storage space you want to retrieve. If an array is passed in, 0 will be returned. If you pass null or undefined here, the function will return the space used by the entire storage area.

Return value

A Promise that will be fulfilled with an integer, bytesUsed, representing the storage space used by the objects that were specified in keys. If the operation failed, the promise will be rejected with an error message.

Browser compatibility