WASM Utils

This repository contains utilities for interfacing with Javascript.

Building

The repository can only be compiled to a WebAssembly binary using GOOS=js and GOARCH=wasm.

$ GOOS=js GOARCH=wasm go build -o xxdk.wasm

Running Unit Tests

This repository depends on syscall/js, which requires a Javascript environment to run, such as running them in a browser. To automate this process, get wasmbrowsertest and follow their installation instructions. Then, tests can be run using the following command.

$ GOOS=js GOARCH=wasm go test ./...

Note, this will fail because exception/throw_js.s contains custom commands that require our modified wasm_exec.js file and wasmbrowsertest does not use it. To get tests to run, temporarily delete the body of exception/throw_js.s during testing.

wasm_exec.js

wasm_exec.js is provided by Go and is used to import the WebAssembly module in the browser. It can be retrieved from Go using the following command.

$ cp "$(go env GOROOT)/misc/wasm/wasm_exec.js" .

Note that this repository makes edits to wasm_exec.js and you must either use the one in this repository or add the following lines in the go importObject on global.Go.

global.Go = class {
    constructor() {
        // ...
        this.importObject = {
            go: {
                // ...
                // func Throw(exception string, message string)
                'gitlab.com/elixxir/wasm-utils/exception.throw': (sp) => {
                    const exception = loadString(sp + 8)
                    const message = loadString(sp + 24)
                    throw globalThis[exception](message)
                },
            }
        }
    }
}