Background
I'm working on a browser addon (webextension API), which is cross-browser (Firefox & Chromium/Chrome/Blink).
I need to use browser.storage.sync (chrome.storage.sync on Chrome) to storage so that data can be synced.
storage.sync limits storage size (128kB), so I've tried these JS compressing library:
(lzutf8 compression results a smaller size)
Using the compress library
Above two both support uint8Array output, but when I tried storing uint8Array into storage.sync they got about 10 times bigger, obviously not really stored in uint8 format.
Then I found compressing to string is the best way to store:
Y1 = LZUTF8.compress(input-data, {outputEncoding: "StorageBinaryString"});
Y2 = LZString.compressToUTF16(input-data)
( Both Y are UTF16 string )
Question
Storing the compressed data Y (string) into Firefox (78) and Chromium (90), the space it occupies in storage.sync different:
- in Firefox: Bytes used =
Y.length. - in Chromium: Bytes used = about 2-3 times larger than
Y.length. WHY?
(The space used can be seen by storage.sync.getBytesInUse(). Both Firefox and Chromium have limitation of same quata: 128k bytes)
I need some explaination. I can't find any doc about how (and what object type) data is stored in storage.sync. Also, I'll appriciate if there is better compressing and storaging (sync supported) solution.
