WebAssembly

Go 1.11 adds an experimental port to WebAssembly.

WebAssembly is described on its home page as:

WebAssembly (abbreviated Wasm) is a binary instruction format for a stack-based virtual machine. Wasm is designed as a portable target for compilation of high-level languages like C/C++/Rust, enabling deployment on the web for client and server applications.

This page will be updated over time with more information relevant to Go's support for WebAssembly.

Example

To compile the basic Go program for the web:

package main

func main() {
	println("Hello, WebAssembly!")
}

Run:

$ GOARCH=wasm GOOS=js go build -o test.wasm main.go

And copy over the HTML & JS support files:

$ cp $(go env GOROOT)/misc/wasm/wasm_exec.{html,js} .

Then serve those three files (wasm_exec.html, wasm_exec.js, and test.wasm) to a web browser.

For a basic HTTP server:

package main

import (
	"flag"
	"log"
	"net/http"
)

var (
	listen = flag.String("listen", ":8080", "listen address")
	dir    = flag.String("dir", ".", "directory to serve")
)

func main() {
	flag.Parse()
	log.Printf("listening on %q...", *listen)
	log.Fatal(http.ListenAndServe(*listen, http.FileServer(http.Dir(*dir))))
}

Now navigate to http://localhost:8080/, click "Run", and you should see the output in the JavaScript debug console.

Interacting with the DOM

See https://tip.golang.org/pkg/syscall/js/

Tutorials + Articles

Building a Calculator with Go and WebAssembly