How to Implement the Or-Channel Pattern in Go

The Or-Channel pattern in Go is implemented by spawning a goroutine for each potential data source and using a select statement to receive from the first channel that sends a value.

func or(c1, c2 <-chan T) <-chan T {
    out := make(chan T)
    go func() {
        select {
        case v := <-c1:
            out <- v
        case v := <-c2:
            out <- v
        }
    }()
    return out
}

This pattern extends to multiple channels by adding more case statements inside the select block.

The Or-Channel Pattern in Go lets your program wait for data from multiple sources and immediately process whichever one arrives first. It is like having several runners race to the finish line; you only care about the first one who crosses it, ignoring the rest until they are done. Use this when you need to handle the earliest available event from a set of concurrent operations.