Well.js is lightweight Promises implemention. It evolved from when-1.8.1 for getting higher performance. The article Promises/A+ Performance Hits You Should Be Aware Of described the benchmark defference of some common promise implementations. In addition, well.js also provide:
- Native cancelable deferred
- Extendable promise through
- Throw exception for uncaught error
It is very fast and compact, and has no external dependencies.