How to Call Go Functions from JavaScript Wasm

You call Go functions from JavaScript by exporting them with //export and using WebAssembly.instantiate to load the module.

//export Add
func Add(a, b int) int {
    return a + b
}

func main() {}

Compile with GOOS=js GOARCH=wasm go build -o main.wasm main.go, then in JavaScript:

const wasm = await WebAssembly.instantiateStreaming(fetch('main.wasm'));
console.log(wasm.instance.exports.Add(2, 3)); // 5

Calling Go functions from JavaScript Wasm lets your web page run Go code directly in the browser. You mark specific Go functions as public, compile them into a special file, and then JavaScript can call them just like normal functions. It's like plugging a Go engine into a JavaScript car.