Why convert FBA to JS?
People want the raw .js to inspect, learn from, or modify a Fitbit app's logic. Because an .fba is really a compressed archive of the app's source code, manifest, and assets, the JavaScript is sitting inside and only needs to be unpacked.
How to convert FBA to JS
7-Zip
Right-click the .fba, choose 7-Zip then Open archive (or rename it to .zip), and extract the .js files from inside.
unzip
Run unzip app.fba -d app_src in a terminal to expand the package and drop the JavaScript and manifest into a folder.
Archive Utility / ditto
Rename to app.zip and double-click, or run ditto -x -k app.fba app_src to unpack the source files.
About these formats
An .fba file is a Fitbit OS App Package, the installable bundle a developer produces when building a Fitbit smartwatch app or clock face with the Fitbit SDK. It is a ZIP archive that holds…
Open .FBA details →
.JS
JavaScript Source File
A JS file is a JavaScript source code file - plain, readable text that powers web page interactivity and server-side apps via Node.js. Open it in any code editor such as VS Code or…
Open .JS details →Quality & what to watch
- The extracted
.jsmay be bundled or minified rather than the original well-formatted source. - You get the app's code and manifest, but the archive is not guaranteed to include everything needed to rebuild it in Fitbit Studio.
- Some
.fbapackages hold a clock face instead of an app, but they extract the same way.
Frequently asked questions
Why can 7-Zip open a .fba file?
.fba is a ZIP-based archive, so archivers read it once you open or rename it as a zip.Is the extracted JavaScript readable?
Do I need to rename .fba to .zip?
unzip can usually read it directly, but renaming to .zip guarantees the archiver recognizes it.
