Golang Result type. Use this in your channels to pass values and errors between goroutine 😉

result.go

package result

import (
	"errors"
	"fmt"
	"sync"
)

type Result[T any] struct {
	Value T
	err   error
}

func Ok[T any](val T) Result[T] {
	return Result[T]{val, nil}
}

func Err[T any](err error) Result[T] {
	var t T
	return Result[T]{t, err}
}

func ErrFromStr[T any](errMsg string) Result[T] {
	var t T
	return Result[T]{t, errors.New(errMsg)}
}

func (r Result[T]) IsOk() bool {
	return r.err == nil
}

func (r Result[T]) IsErr() bool {
	return r.err != nil
}

func (r *Result[T]) GetError() error {
	return r.err
}

// Error Interface
func (r *Result[T]) Error() string {
	return r.err.Error()
}

func Equal[T comparable](r, other Result[T]) bool {
	if r.IsOk() && other.IsOk() {
		return r.Value == other.Value
	}
	if r.IsErr() && other.IsErr() {
		return r.Error() == other.Error()
	}
	return false
}

func ExampleWithChannel() {
	type payload struct {
		Meaning int
	}
	ch := make(chan Result[payload], 2)
	go func() {
		ch <- Ok(payload{42})
	}()
	go func() {
		ch <- Err[payload](errors.New("go func error happened ..."))
	}()

	for range 2 {
		result := <-ch
		if result.IsErr() {
			fmt.Fprintf(os.Stderr, "Error from goroutine: %+v\n", result)
		}
		if result.IsOk() {
			fmt.Printf("From my goroutine: %+v\n", result)
		}
	}
	close(ch)
}