ayepromise is a teeny-tiny promise library. It promises to pass the Promises/A+ 1.1 Compliance Test Suite.
Supports modern browsers (i.e. IE > 8).
ayepromise wants to be as small as possible (~180 LOC, ~1200 bytes minified), staying compatible to Q while fully implementing the spec. It's licensed under WTFPL and/or BSD.
ayepromise tries to be fully compatible with kriskowal's Q in such a way that you can always replace ayepromise with Q. (There's a catch: ayepromise tries to strictly follow Promises/A+ 1.1 and will differ where Q does not.) It will not however try to implement anything close to the full feature set. Check test/CompatibilitySpecRunner.html to see ayepromise's test suite executed against Q.
For the browser, first install dependencies via npm install and bower install and then open test/SpecRunner.html.
For NodeJS install dependencies via npm install and run npm test. This includes the Promise/A+ Compliance Test Suite.