Kotlin/JS vs Transcrypt
Kotlin/JS
kotlinlang.orgTranscrypt
transcrypt.orgSide by side
| Figure | Kotlin/JS | Transcrypt |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Web | Yes | Yes |
| Windows | Yes | Yes |
| macOS | Yes | Yes |
| Linux | Yes | Yes |
| Self-hosted | — | Yes |
| Plans published | 1 | 1 |
| Spec score · Code Transpilers | 7.8 (#15) | 8.0 (#9) |
| Debugging | The Kotlin Multiplatform Gradle plugin automatically generates JavaScript source maps for project builds. | Transcrypt provides multi-level source maps so developers can debug generated JavaScript from Python source code. |
| Integrations | JetBrains provides Kotlin wrappers for React and other JavaScript frameworks, including support for React Redux, React Router, and styled-components. | The examples page includes integrations or demos involving jQuery, React, Fabric.js, D3.js, Plotly.js, and Riot. |
| Purpose | Kotlin/JS transpiles Kotlin code, the Kotlin standard library, and compatible dependencies to JavaScript. | Transcrypt compiles Python source code into JavaScript for browser applications. |
| Support | The Kotlin documentation directs users to the #javascript channel in Kotlin Slack to discuss Kotlin/JS with the community and team. | The FAQ recommends Stack Overflow for help and says commercial support is available on demand. |
Plans
In their own words
Kotlin/JS
Kotlin/JS is a Kotlin compiler target that converts Kotlin code, the Kotlin standard library, and compatible dependencies into JavaScript. Projects can target browsers or Node.js, including server-side and serverless applications. It supports ES5, ES2015, and ES2020 output, as well as ESM, CommonJS, UMD, and AMD modules. Projects use the Kotlin Multiplatform Gradle plugin for configuration, bundling, and JavaScript dependencies from npm. Kotlin/JS can share logic between web frontends and JVM backends, or across Android, iOS, and web clients. Kotlin wrappers are available for React and other JavaScript frameworks, including React Redux, React Router, and styled-components. Browser tests can use Karma or an experimental browser testing DSL; Node.js projects use Mocha. The documentation notes that Karma is deprecated and is not expected to receive new features or bug fixes. The Gradle plugin generates JavaScript source maps for builds. Kotlin/JS is open source and free at free, and is listed for Linux, macOS, web, and Windows.
Transcrypt
Transcrypt compiles Python source code into JavaScript for browser applications. It converts a substantial subset of Python into JavaScript 6, with optional minification, and supports features including multiple inheritance, async/await, comprehensions, and modules. Developers can call JavaScript functions from Python and use browser DOM functions and JavaScript libraries. The distribution includes optional static type validation and consistency checks, plus multilevel source maps for tracing generated JavaScript back to the original Python. Transcrypt can also compile Python server code for Node.js and use Node libraries with require(). The project recommends installing it as a Python package with pip and documents testing on Windows, Linux, and OSX. Its focus is browser development and JavaScript libraries rather than desktop Python libraries. Because code is precompiled, Python exec and eval are unsupported, although JavaScript eval is supported. C and C++ libraries are not directly supported for browser use without special measures such as compiling them to asm.js. Transcrypt is free and open source under Apache 2.0.