IP Address with CIDR Notation

const re = new RegExp("(?:(?:25[0-5]|2[0-4]\\d|[01]?\\d\\d?)\\.){3}(?:25[0-5]|2[0-4]\\d|[01]?\\d\\d?)\\/(?:3[0-2]|[12]?\\d)", "g");
const input = "10.0.0.0/8";
const matches = [...input.matchAll(re)];
console.log(matches.map(m => m[0]));

import re

pattern = re.compile(r"(?:(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\/(?:3[0-2]|[12]?\d)")
input_text = "10.0.0.0/8"
for m in pattern.finditer(input_text):
    print(m.group(0))

package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`(?:(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\/(?:3[0-2]|[12]?\d)`)
	input := `10.0.0.0/8`
	for _, match := range re.FindAllString(input, -1) {
		fmt.Println(match)
	}
}