error.go

//go:build js

package goji

import (
	"reflect"
	"syscall/js"
)

func init() {
	Error = errorJS(js.Global().Get("Error"))
}

type errorJS js.Value

// Error is a wrapper for the Error global object.
//
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error
var Error errorJS

// New wraps the Error constructor.
//
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/Error
func (e errorJS) New(message string) ErrorValue {
	res := js.Value(e).New(message)
	return ErrorValue(res)
}

var _ (error) = (ErrorValue)(js.Undefined())

// ErrorValue is an instance of
type ErrorValue js.Value

// Error wraps the Error toString prototype method.
//
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/toString
func (v ErrorValue) Error() string {
	res := js.Value(v).Call("toString")
	return res.String()
}

// WrapError is a helper func that returns an ErrorValue with the message
// set to the given error's `Error()` value and the name set to the
// given error's reflected type name.
func WrapError(err error) ErrorValue {
	wrap := Error.New(err.Error())
	name := reflect.TypeOf(err).Elem().Name()
	if name != "" {
		js.Value(wrap).Set("name", name)
	}
	return wrap
}