VSCode Web Extension incorporating Rust WASM

After fighting for a long time with webpack to get it to generate WASM loading code that would work with vscode web extensions (see https://code.visualstudio.com/api/extension-guides/web-extensions#web-extension-main-file for why this is non-trivial), I understood that I will need to change the webpack WASM loading code. I even found documentation saying it's possible. When I tried, I got an error message saying I just need to call EnableWasmLoadingPlugin.setEnabled(), which was very encouraging, however, I couldn't find a way to do that, so I had to patch webpack to export it. PR submitted.

To install:

git submodule add -b enable-wasm-loader https://github.com/SonOfLilit/webpack
npm i ./webpack
npm i vscode-web-wasm-webpack-plugin

In webpack.config.js:

const wasmPlugin = require("vscode-web-wasm-webpack-plugin");

const webExtensionConfig = {
...
  output: {
    ...
    enabledWasmLoadingTypes: ["async-vscode"],
    wasmLoading: "async-vscode",
  },
  plugins: [
    ...
    new wasmPlugin.ReadFileVsCodeWebCompileAsyncWasmPlugin(),
  ],
...

In web/extension.ts:

export function activate(context: vscode.ExtensionContext) {
  __webpack_public_path__ =
    context.extensionUri.toString().replace("file:///", "") + "/dist/web/";
  // ..

  // the require() must happen after __webpack_public_path__ has been set, so can't happen in the global scope, but it doesn't have to be in this function
  require("rust-wasm").then((rust: any) => {
    vscode.window.showInformationMessage(rust.greet());
  });

  // ..
}

If you use typescipt, you will want to add webpack to tsconfig.json's exclude list:

...
	"exclude": [
		"node_modules",
		"webpack",
		".vscode-test"
	]
...

Talk to me

This was the longest task in the history of my Regex Syntax for Humans project, Kleenexp, longer that writing the compiler or porting it to rust or writing a vscode extension. It took almost a week of banging my head against the wall to find a way to achieve this. So if this was useful to you, please drop me a word to help me feel like I was doing something useful :-)