JSweet vs SWC

JSweet converts Java programs into TypeScript and JavaScript for browsers, mobile Web views, or Node.js. It uses Oracle's Java compiler alongside Microsoft's TypeScript compiler to generate type-checked JavaScript. The project describes the output as regular JavaScript that can work directly with JavaScript programs and libraries. Listed language features include Java-to-TypeScript syntax mapping, Java constructs, async/await, and ECMAScript targets from ES3 to ES6. JSweet lists support for more than 1,000 JavaScript libraries, frameworks, and plugins, packaged as Maven artifacts called candies. It provides Eclipse, Maven, and Gradle plugins, and names Angular, Cordova, Node.js, and Three.js among example integrations. Generated programs can use CommonJS, AMD, or UMD modules and run in browsers or Node.js. A debug mode supports debugging Java code in a browser. Setup instructions call for Git, Node.js, and Maven, then use Maven to generate JavaScript from a quickstart project. JSweet is open source and free, and is presented for Java developers building web and mobile HTML5 applications with JavaScript libraries and frameworks.

SWC is a free, extensible Rust-based platform for tools that compile and bundle JavaScript and TypeScript. It transforms modern JavaScript and TypeScript into code intended for major browsers, and supports minification, WebAssembly transforms, and custom plugins. Its core API parses ECMAScript, TypeScript, and Flow syntax; the documentation describes that API as mainly useful to build-tool authors. Integrations include webpack, Rspack, and Jest, while Next.js, Parcel, and Deno are among the tools named as users. A WebAssembly module can transform code synchronously inside a browser. SWC can be installed as prebuilt binaries or built from source, with packages documented for npm, Yarn, pnpm, Bun, and Deno. The site states that it is 20x faster than Babel on one thread and 70x faster on four cores. The bundling documentation says that feature will be dropped in v2 and recommends SWC-based bundlers instead. It also warns that its polyfill usage mode is less efficient than Babel for certain dynamically computed property expressions.