JavaScript / ECMAScript

IP Address with CIDR Notation in JS

Match IPv4 addresses with CIDR prefix notation such as 10.0.0.0/8 or 192.168.1.0/24.

Pattern

regexJS

(?:(?: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)   (flags: g)

JavaScript / ECMAScript code

jsJavaScript

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]));

Uses `String.prototype.matchAll` for global iteration (Node 12+ / all modern browsers).

How the pattern works

The IPv4 portion uses alternation to strictly validate each octet in the 0–255 range (same as the standalone IPv4 pattern). \/(?:3[0-2]|[12]?\d) appends a / and a CIDR prefix constrained to 0–32.

Examples

Input

10.0.0.0/8

Matches

10.0.0.0/8

Input

192.168.1.0/24

Matches

192.168.1.0/24

Input

999.0.0.0/33

No match

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Same pattern, other engines

Python (re)

Supported

See how this pattern looks (and behaves) in Python's stdlib `re` module.

Go (RE2)

Supported

See how this pattern looks (and behaves) in Go's `regexp` package (RE2 engine).

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