*TL;DR-* commons-validator-js <https://github.com/wix/commons-validator-js> is a partial JavaScript port of commons-validator (currently EmailValidator and DomainValidator).
*Long version-* commons-validator's EmailValidator is by far the best and most comprehensive email validator out there. Unfortunately, there's no equivalent JavaScript implementation. Specifically, I couldn't find a JavaScript email validation library that A) works offline, and B) validates top level domains (e.g. fails "[email protected]"). Introducing: commons-validator-js, a JavaScript version of EmailValidator and DomainValidator, each accompanied by a complete test case. The only challenge was working around some issues with JavaScript's regexp implementation, e.g. no support for lookbehind or "\p{...}". Eventually I commented-out 2-3 tests that still fail, but these were edge cases that didn't really bother me.
