How can i get details error message when a package is not found?

[5idu]

question background

when i run the script below, i got a error message: GoError: Invalid module at github.com/dop251/goja_nodejs/require.(*RequireModule).require-fm (native) but i want detailed error information, such as which package does not exist. thanks!

const xx = require('xx')
const notfound = require('notfound package')
console.log(notfound)

[dop251]

You can't get it from the error itself, because it's a value, not type, but you can get the location from the stacktrace, which will point to the line of code that contains the require. If you are doing something like dynamic require, you can write a wrapper function.

[5idu]

maybe someone can use it in the future!

func formatGojaErr(script string, err error) error {
    ex, ok := err.(*goja.Exception)
    if ok {
        if strings.Contains(ex.String(), "Invalid module") {
            stackframes := strings.Split(ex.String(), "\n")
            if len(stackframes) > 2 {
                lines := strings.Split(stackframes[2], ":")
                if len(lines) > 2 {
                    line, err := strconv.Atoi(lines[1])
                    if err == nil {
                        errLine := strings.Split(script, "\r\n")[line-1]
                        if strings.Contains(errLine, "require") {
                            re := regexp.MustCompile(`['"]([^'"]+)['"]`)
                            match := re.FindStringSubmatch(errLine)
                            if len(match) > 0 {
                                return errors.New("Invalid module: " + match[1])
                            }
                        }
                    }
                }

            }
        }
    }

    return err
}