channels

func CancelOnErr ¶

func CancelOnErr(cancel context.CancelFunc, f func() error) func() error

CancelOnErr allows calling a closure that may return an error, and if it does call the cancel function passed in. Useful when used repeatedly in the same func.

func ReadAllFrom ¶

func ReadAllFrom[T any](ctx context.Context, ch <-chan T, f func(value T) error) (err error)

ReadAllFrom reads all items from a channel and calls the closure for each item. e.g.

intChan := make(chan int, 10)
// Do something to fill intChan
ctx, cancel := context.WithCancel(context.Background())
err := ReadFrom(ctx, intChan, func(i int) error {
	if i%2 == 0 { // Simulate an error
		return fmt.Errorf("Oops! We can't do even: %d", i)
		cancel()
	}
	fmt.Println(i)
	return nil
})
if err != nil {
		cancel()
		return err
}

func WriteTo ¶

func WriteTo[T any](ctx context.Context, ch chan<- T, value T) (err error)

WriteTo writes an item to a channel of that items type while allowing for cancellation. e.g.

		// See https://goplay.tools/snippet/bBq3PpAeMa0
		intChan := chan int
		ctx,cancel := context.WithCancel(context.Background())
		err := channels.WriteTo(ctx,intChan,10)
	  if err != nil {
       cancel()
				return err
		}
   close(intChan)

In the case of a channel of an interface, e

//See https://goplay.tools/snippet/m6M8-GwfyUq
type Suiter interface {
	Suit()
}
type Hearts struct{}
func (Hearts) Suit() {}
func Example() {
	suitChan := make(chan Suiter, 10)
	ctx := context.Background()
	err = WriteTo[Suiter](ctx, suitChan, Hearts{})
	if err != nil {
			cancel()
			return err
	}
	close(suitChan)
}