This is an unofficial ANTLR4 runtime for JavaScript. The main difference with the official one is that this runtime is written with Google closure compiler compatible code. It is an almost direct rewrite of the Java runtime and it reports an ~ 98% coverage regarding type checking.
DISCLAIMER
As there are currently no tests that check how this runtime behaves I do not recommend using it in production code.
The need for this came when I was working on a project that used Clojure(Script) and I wanted to re-use code written with ANTLR4 Java runtime in JavaScript which was impossible with the current JavaScript runtime, plus I wanted all the benefits of the Google closure compiler.
For this to work you will probably need a new ANTLR4 target that will generate the parser and the lexer with code compatible with this runtime. I have a branch in my ANTLR4 fork that does that.
Because currently there are no tests I would really like to have someone more experienced than me with ANTLR4 help with tests. I have tested it with some (not so trivial) grammars but no automated tests yet.
The same as ANTLR4 (I guess?)