Golang WASM Async Function

package main import ( "fmt" "syscall/js" ) type fn func(this js.Value, args []js.Value) (any, error) var ( jsErr js.Value = js.Global().Get("Error") jsPromise js.Value = js.Global().Get("Promise") ) func asyncFunc(innerFunc fn) js.Func { return js.FuncOf(func(this js.Value, args []js.Value) any { handler := js.FuncOf(func(_ js.Value, promFn []js.Value) any { resolve, reject := promFn[0], promFn[1] go func() { defer func() { if r := recover(); r != nil { reject.Invoke(jsErr.New(fmt.Sprint("panic:", r))) } }() res, err := innerFunc(this, args) if err != nil { reject.Invoke(jsErr.New(err.Error())) } else { resolve.Invoke(res) } }() return nil }) return jsPromise.New(handler) }) } func argsEvenOdd(this js.Value, args []js.Value) (any, error) { if len(args)%2 == 0 { return nil, fmt.Errorf("#args is even") } return "#args is odd", nil } func main() { js.Global().Set("argsEvenOdd", asyncFunc(argsEvenOdd)) select {} } 

argsEvenOdd(1, 2) .then(res => console.log(res)) .catch(err => console.error(err)) // will be catched argsEvenOdd(1) .then(res => console.log(res)) // will be logged .catch(err => console.error(err))