Contributing

Thanks for thinking about contributing to Espruino! Anything you can add is hugely appreciated, but please can you follow a few simple rules:

Keep the same coding style (See Coding Style below)
Ensure that you are not contributing someone else's code, and that you are willing to add your code under Espruino's MPL Licence
Make sure that what you do doesn't break the Espruino board or the other boards we build for. We can't check all the boards for every commit, so if you break something you'll annoy a whole bunch of people.
Be aware that Espruino is designed for Microcontrollers - with very low amounts of flash and memory. Both are at a premium so don't statically allocate variables or do other stuff that will use up memory.
Avoid randomly adding newlines, spaces, refactoring everything or renaming things to your own personal style (some things really could do with renaming, but please check first or we may reject your pull request)
Don't add a whole bunch of indirection/abstraction for the sake of it - it'll probably just use of more of our precious memory.
If you add a new API, try and make it familiar to Arduino/JavaScript users.

Target Areas

We'll keep the outstanding issues in GitHub's issue list, but general stuff that would really help us is:

Tests. If something doesn't work, please make a test for it. Even if you don't fix it it'll help others greatly. Bonus points if it's in a pull request :)
Documentation. Improving the documentation (either the EspruinoDocs project, or the auto-generated reference) would be fantastic.
Duplication. If the same code is used for multiple platforms, try and make sure it's shared, not duplicated.
Remove hard-coded stuff. Various things like the SPI filesystem are still hard-coded with ifdefs for each board - we want all that stuff to be generated from build_platform_info.py
Speed. There are a few areas this could be improved - but please benchmark what you're doing both before and afterwards on the Espruino board to check that what you've done helps
Memory Usage. Both RAM and Flash are at a premium. Ways of reducing this (including stack usage) and making usage more efficient are really appreciated.
JavaScript compliance (without affecting speed or memory usage too much).

The rough coding style is as follows, but you should get a good idea from the code. If we've missed anything obvious please let us know!

2 Spaces for indents
Open curly braces on the same line
No Tabs used
Use bool for booleans - not int
// comments for single lines, /* ... */ for multiple lines
Half-hearted Doxygen compatibility: use ///< for function declaration documentation (if on same line), and /** ... */ if doing it right before a function
Use new lines sparingly (only where it really makes sense)