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const jsii = require('jsii');
// Define a TypeScript class
class HelloWorld {
sayHello() {
return 'Hello, world!';
}
}
// Export the class using jsii
module.exports = { HelloWorld };
// In Python, you can now use the generated bindings
# from your_module import HelloWorld
# hello = HelloWorld()
# print(hello.sayHello())TypeScript to Java
This feature allows you to write a class in TypeScript and then use it in Java by generating the necessary bindings.
const jsii = require('jsii');
// Define a TypeScript class
class Calculator {
add(a, b) {
return a + b;
}
}
// Export the class using jsii
module.exports = { Calculator };
// In Java, you can now use the generated bindings
// Calculator calculator = new Calculator();
// int result = calculator.add(1, 2);
// System.out.println(result);TypeScript to C#
This feature allows you to write a class in TypeScript and then use it in C# by generating the necessary bindings.
const jsii = require('jsii');
// Define a TypeScript class
class Greeter {
greet(name) {
return `Hello, ${name}!`;
}
}
// Export the class using jsii
module.exports = { Greeter };
// In C#, you can now use the generated bindings
// Greeter greeter = new Greeter();
// string greeting = greeter.greet("World");
// Console.WriteLine(greeting);SWIG (Simplified Wrapper and Interface Generator) is a tool that connects programs written in C and C++ with various high-level programming languages. Unlike jsii, which focuses on TypeScript, SWIG is used for C/C++ and supports a wide range of languages including Python, Java, and C#.
jsii allows code in any language to naturally interact with JavaScript classes. It is the technology that enables the
AWS Cloud Development Kit to deliver polyglot libraries from a single codebase!
A class library written in TypeScript can be used in projects authored in TypeScript or Javascript (as usual), but also in Python, Java, C# (and other languages from the .NET family), ...
Head over to our documentation website!
The jsii toolchain is spread out on multiple repositories:
jsii compiler is maintained (except releases
in the 1.x line)jsii-rosetta sample code transliteration tool
is maintained (except releases in the 1.x line)@jsii/spec, the package that defines the .jsii assembly specificationjsii-config, an interactive tool to help configure your jsii packagejsii-pacmak, the bindings generator for jsii packagesjsii-reflect, a higher-level way to process .jsii assemblies1.x release lines of jsii and jsii-rosettaHere's a collection of blog posts (in chronological order) related to jsii:
:information_source: If you wrote blog posts about
jsiiand would like to have them referenced here, do not hesitate to file a pull request to add the links here!
The applicable Maintenance & Support policy can be reviewed in SUPPORT.md.
The current status of jsii compiler releases is:
| Release | Status | EOS | Comment |
|---|---|---|---|
5.9.x | Current | TBD |  |
5.8.x | Maintenance | 2026-02-15 |  |
5.7.x | Maintenance | 2025-09-15 |  |
jsii is distributed under the Apache License, Version 2.0.
See LICENSE and NOTICE for more information.
See CONTRIBUTING.
Thanks goes to these wonderful people (emoji key):
This project follows the all-contributors specification. Contributions of any kind welcome!
FAQs
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