File Content: index.js import ipRegex from "ip-regex"; const defaultOpts = {exact: false}; const v4str = `${ipRegex.v4().source}\\/(3[0-2]|[12]?[0-9])`; const v6str = `${ipRegex.v6().source}\\/(12[0-8]|1[01][0-9]|[1-9]?[0-9])`; // pre-compile only the exact regexes as global flag makes regex objects stateful const v4exact = new RegExp(`^${v4str}$`); const v6exact = new RegExp(`^${v6str}$`); const v46exact = new RegExp(`(?:^${v4str}$)|(?:^${v6str}$)`); const cidrRegex = ({exact} = defaultOpts) => exact ? v46exact : new RegExp(`(?:${v4str})|(?:${v6str})`, "g"); export const v4 = cidrRegex.v4 = ({exact} = defaultOpts) => exact ? v4exact : new RegExp(v4str, "g"); export const v6 = cidrRegex.v6 = ({exact} = defaultOpts) => exact ? v6exact : new RegExp(v6str, "g"); export default cidrRegex; Submit