Go (GOOS=js GOARCH=wasm) + Vite

add.go

package main

//go:wasmexport add
func add(a int32, b int32) int32 {
	return a + b
}

func main() {}



// GOOS=js GOARCH=wasm go build -o main.wasm

add.js

import goWorker from "@/worker?worker"; // https://vite.dev/guide/features.html#import-with-query-suffixes
let worker = null

const initWorker = () => {
    if (worker !== null) return
    worker = new goWorker();
    worker.onmessage = ({ data }) => {
        let { action, payload } = data;
        switch (action) {
            case "ready":
                console.log("worker ready", data);
                worker.postMessage({ action: "call", payload: null });
                break;
            case "result":
                console.log("result", action, payload);
                break;
            default:
                console.log("unknown action", action, payload);
                break;
        }
    };
}

initWorker()

worker.js

import wasmUrl from "./main.wasm?url"; // https://vite.dev/guide/features.html#accessing-the-webassembly-module
import "./wasm_exec.js"; // wasm_exec.js located in lib/wasm/wasm_exec.js just copy to project

const responsePromise = fetch(wasmUrl);
const go = new Go();
let exports;

WebAssembly.instantiateStreaming(responsePromise, go.importObject)
    .then(async ({ instance }) => {
        exports = instance.exports;
        await go.run(instance);
        postMessage({ action: "ready", payload: null });
    })
    .catch((err) => {
        console.error("Worker failed to load module: ", err);
    });

onmessage = ({ data }) => {
    const { action, payload } = data;
    switch (action) {
        case "call":
            const res = exports.add(3,5);
            postMessage({ action: "result", payload: res });
            break;
        default:
            console.log("unknown action", action);
    }
};