~/Golang Channel Direction Explained

Mar 13, 2020

Golang channels support direction to enforce if a function can only send or receive values. This increases code safety and clarity.

Direction Types

chan T means send and receive permitted.
chan<- T means send only.
<-chan T means receive only.

Example Usage

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func send(ch chan<- int, val int) {
    ch <- val // Only sending is allowed
}

func receive(ch <-chan int) int {
    return <-ch // Only receiving is allowed
}

func main() {
    ch := make(chan int)
    go send(ch, 10)
    val := receive(ch)
    fmt.Println(val)
}

Passing directional channels prevents misuse. For more, see Golang Tour: Channels and Go Spec.