ANTLR4 TypeScript Runtime (antlr4ng)

antlr4ng is an alternative, TypeScript-first runtime for ANTLR4 grammars, specifically designed to be used with the `antlr-ng` parser generation tool. Currently stable at version `3.0.16`, it receives frequent point releases addressing bugs and introducing minor enhancements. Unlike the original ANTLR4 JavaScript runtime, `antlr4ng` operates identically across Node.js and browser environments and is built with strict TypeScript nullability checks. It requires an ES2022 (ES6) compatible runtime for features like static initialization blocks and private class fields. While implementing nearly all features of the Java ANTLR4 runtime, it notably omits the `UnbufferedCharStream` class. Developers migrating from other ANTLR4 JavaScript runtimes will need to adjust code for stricter null handling and renamed internal members.