**AssemblyScript** compiles a strict subset of [TypeScript](http://www.typescriptlang.org) (basically JavaScript with types) to [WebAssembly](http://webassembly.org) using [Binaryen](https://github.com/WebAssembly/binaryen). It generates lean and mean WebAssembly modules while being just an `npm install` away.
The core team members and most contributors do this open source work in their free time. If you use AssemblyScript for a serious task or plan to do so, and you'd like us to invest more time on it, [please donate to our OpenCollective](https://opencollective.com/assemblyscript). By sponsoring this project, your logo will show up above. Thank you so much for your support!
> AssemblyScript was frictionless. Not only does it allow you to use TypeScript to write WebAssembly, [...] it also produces glue-free WebAssembly modules that are very small with decent performance. – Surma, [Replacing a hot path in your app's JavaScript with WebAssembly](https://developers.google.com/web/updates/2019/02/hotpath-with-wasm) (Feb 16, 2019)
> Perhaps the fundamental issue [to get a small .wasm file] is that JavaScript is the only language for which the Web runtime is a perfect fit. Close relatives that were designed to compile to it, like TypeScript, can be very efficient as well. But languages like C, C++, Rust, and so forth were not originally designed for that purpose. – Alon Zakai, [Small WebAssembly Binaries with Rust + Emscripten](https://kripken.github.io/blog/binaryen/2018/04/18/rust-emscripten.html) (Apr 18, 2018)
> JavaScript's heyday as the only browser language is over, but most web developers are used to writing JavaScript, and learning a new syntax just to get access to WebAssembly is not (always) ideal. If only there was something in to bridge the gap… – Jani Tarvainen, [TypeScript is the bridge between JavaScript and WebAssembly](https://malloc.fi/typescript-bridge-javascript-webassembly) (Feb 20, 2018)
> I do think [compiling TypeScript into WASM] is tremendously useful. It allows JavaScript developers to create WASM modules without having to learn C. – Colin Eberhardt, [Exploring different approaches to building WebAssembly modules](http://blog.scottlogic.com/2017/10/17/wasm-mandelbrot.html) (Oct 17, 2017)
For general usage instructions, please refer to the [documentation](https://docs.assemblyscript.org) instead. The following sets up a *development environment* of the compiler, for example if you plan to make a pull request:
Note that a fresh clone of the compiler will use the distribution files in `dist/`, but after an `npm clean` it will run [the sources](./src) directly through ts-node, which is useful in development. This condition can also be checked by running `asc -v` (it is running the sources if it states `-dev`). Also please see our [contribution guidelines](./CONTRIBUTING.md) before making your first pull request.
To build an UMD bundle to `dist/assemblyscript.js` (depends on [binaryen.js](https://github.com/AssemblyScript/binaryen.js)), including a browser version of asc to `dist/asc.js` (depends on assemblyscript.js):
