cmp.Or()

This is a small demonstration of the cmp.Or() function provided by the Go standard library.

cmp.Or() returns the first of its arguments that is not equal to the zero value. If no argument is non-zero, it returns the zero value.

package main

import (
	"cmp"
	"fmt"
	"os"
)

func main() {
	ip := os.Getenv("IP")
	if ip == "" {
		ip = os.Getenv("IP_ADDRESS")
	}

	if ip == "" {
		ip = "127.0.0.1"
	}
	fmt.Println("IP:", ip)

	// This is equivalent to all previous statements	
	myIP := cmp.Or(os.Getenv("IP"), os.Getenv("IP_ADDRESS"), "127.0.0.1")
	fmt.Println("myIP:", myIP)
}

Executing it generates the following output:

$ go run /tmp/or.go
IP: 127.0.0.1
myIP: 127.0.0.1

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