A channel can be made read-only to whoever receives it, while the sender still has a two-way channel to which they can write. For example:
func F() <-chan int {
// Create a regular, two-way channel.
c := make(chan int)
go func() {
defer close(c)
// Do stuff
c <- 123
}()
// Returning it, implicitly converts it to read-only,
// as per the function return type.
return c
}
Whoever calls F(), receives a channel from which they can only read. This is mostly useful to avoid potential misuse of a channel at compile time. Because read/write-only channels are distinct types, the compiler can use its existing type-checking mechanisms to ensure the caller does not try to write stuff into a channel it has no business writing to.
Copied from: https://stackoverflow.com/questions/13596186/whats-the-point-of-one-way-channels-in-go
