dreagonmon / littlefs-js

littlefs wrapped in javascript... for some reason...

A javascript wrapper for the little filesystem

This project puts together two things that should probably never go together:
embedded system filesystems, and web-side javascript.

The result is a fully functional javascript API for littlefs, complete with simulated block devices. This was all built using emscripten, a backend for the LLVM that can compile C to javascript. There's no smoke and mirrors here, this is actually running littlefs in your browser.

• original littlefs-js - https://github.com/littlefs-project/littlefs-js
• littlefs - https://github.com/geky/littlefs
• emscripten - https://github.com/kripken/emscripten

Difference from the original littlefs-js

• link to the littlefs library via git submodule.
• upgrade littlefs to v2.5.1
• comfigured to only generate .js file, this will allow easier integrations (but worse performance).
• suppout asynchronous block device's api, which make it possible to directly access real devices via Web Bluetooth, Web USB, Web Serial and so on.
• all filesystem's operations are asynchronous, include tell and seek, don't forget to await.

Try the demo

You need compile the project before run the demo. This will generate the lfs.js.

# install emcc (emscripten) 3.1.31 first.
make

You can try it with node demo.js or deno run demo.js.

Useage

lfs.js and lfs_js.js are required. and only es module are supported.

You can implement your own block device by extend BlockDevice class. Refer to MemoryBlockDevice class for example.

• read and prog functions are required. erase and sync are optional.
• read, prog, erase, sync functions can be asynchronous, and return a number. 0 means success, < 0 means failed, and the error code return to the io-operation-caller.
• outside lfs_js.js, use LFSModule.HEAPU8 to access raw memory.
• this.block_size and this.block_count are required.
• write_size, read_size, cache_size don't affect the data on the filesystem. so they are all set to this.block_size.