j4ts

j4ts is a partial translation of the Java standard library (JRE) to JavaScript, forked from GWT's Java emulation and transpiled via JSweet. This NPM package (j4ts) provides the generated JavaScript and TypeScript definitions for use in JavaScript/TypeScript projects. Currently at version 0.7.2, it targets JSweet v2 and requires at least Java 8. It offers core Java collections, utilities, and NIO-like buffers. The package is ESM-compatible since v0.7.x. Compared to other Java-to-JS solutions (e.g., GWT, CheerpJ), j4ts is lightweight and designed for gradual migration of Java code to TypeScript. Release cadence is irregular, driven by j4ts upstream.