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://bugzil.la/1385832
This is an asynchronous function that returns a
let gettingSpace = browser.storage.<storageType>.getBytesInUse( keys // null, string, or array of strings )
<storageType> can only be
storage.local because of this bug.
A key (string) or keys (an array of strings) to identify the item(s) whose storage space you want to retrieve. If an empty array is passed in, 0 will be returned. If you pass
undefinedhere, the function will return the space used by the entire storage area.
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.
BCD tables only load in the browser
Note: This API is based on Chromium's
chrome.storage API. This documentation is derived from
storage.json in the Chromium code.