WAstyle

AStyle code formatter compiled to WebAssembly, for Node.js and the browser.

Install

Install via NPM:

$ yarn add wastyle

Usage

Firstly, you need to initialize AStyle WASM library with init function.

Unfortunately this step couldn't be done automatically since you need make Webpack emit the AStyle WASM binary to your dist directory and tell us its URL. Since we support running in browser mainly, so I don't want to write code to detect Node.js to increase your Webpack bundle size. So in both Node.js and Webpack this step must be done.

In Node.js, call init with a Buffer from fs.readFile or fs.readFileSync:

const fs = require("fs");
const util = require("util");
const wastyle = require("wastyle");

util.promisify(fs.readFile)("wastyle/dist/astyle.wasm")
.then(data => wastyle.init(data))
.then(() => console.log("WAstyle is ready!"))
.catch(err => console.error(err));

In Webpack, I recommend you to use file-loader to emit the AStyle WASM binary to your dist directory and get its URL. See NeekSandhu/onigasm#2.

Note that Webpack has a very simple built-in WASM loader, which will load a WASM file (detected by its magic header) as a compiled and instantiated WASM instance. But it doesn't support passing imports to WASM module. So it WILL fail since the AStyle WASM binary needs WASI to run. To disable the build-in WASM loader and force file-loader to produce the file URL, use this rule: (webpack/webpack#6725)

{
  test: /\.wasm$/,
  loader: "file-loader",
  type: "javascript/auto"
}

In your code, initialize WAstyle with:

import { init, format } from "wastyle";
import astyleBinaryUrl from "wastyle/dist/astyle.wasm";

init(astyleBinaryUrl).then(() => console.log("WAstyle is ready!"));

The init function will compile and instantiate the Astyle WASM binary asynchronously. Will throw an error if failed.

After initialization, call the synchronous function format to use Astyle:

const [success, result] = format("#include <cstdio>\nint main(){int 🦄,a,*b=a,c=🦄*2,*d=nullptr;return -1;}", "pad-oper style=google");
console.log(result);
// #include <cstdio>
// int main() {
//     int 🦄, a, *b = a, c = 🦄 * 2, *d = nullptr;
//     return -1;
// }

Besides, you can use wastyle/dist/wastyle-optimize-size.wasm to reduce your Webpack dist's size.

Performance

Tested on Chrome 80.0.3987.122 on an i7-6600U laptop, formatting this C++ file takes 15ms with wastyle/dist/wastyle.wasm and 40ms with wastyle/dist/wastyle-optimize-size.wasm in average of 100 samples.

Development

You'll need emcc to build the Astyle WASM binary. Follow this guide to install it.

$ yarn build      # Build TypeSrript
$ yarn build:wasm # Build WASM

License

This project is licensed under the MIT license.

Astyle code formatter (Artistic Style) is also licensed under the MIT license. You can find its license in the astyle folder.