Promesse is a Promises/A+ compliant Promise library. This implementation passes all the tests of the standard test suite.
Why oh Why?
I've written it because I love using promises in JS and I like to know how the tools I use work.
There are many implementations out there, I wanted mine to be very small and written as much as possible in functional programming style.
I'm rather happy about the result:
- 98 lines of code (no comments, comments are for the weak), so probably one of the shortest implementations out there
- looks a bit like Haskell :)
It's been a really enriching experience, now I know a lot more about the subtleties of promises than any documentation would tell.
Besides, working against an existing huge test suite is a cool programming exercise.
Obviously this is a toy project, but I'd be interested in having feedback on:
- does the code make sense to you? or did I just write some "write-only" software?
- can you see ways to make it smaller without making it too obscure / unreadable?
- can you see other functional patterns that I could use to make the code more concise?
This is probably not very useful since promises are standard, but, if for some reason you need to:
npm i --save aplus-promesse
git clone https://github.com/djfm/promesse cd promesse npm i npm test
There are two test suites, the one from Promises/A+, and the one I wrote to help me when I did not understand the feedback from the official tests.
Making it Smaller
Now that the library is working and tested, I want to make it smaller in terms of number of lines of code.
The rules are:
- lines must not exceed 80 columns
- block declarations (by that I mean a declaration that takes more than one line or a succession of one line declarations) and top level declarations are followed with one blank line at least
- more subjectively: the code needs to remain easy to read