const regex = /^(2[0-4]\d|25[0-5]|1\d\d|\d\d?)\.(?1)\.(?1)\.(?1)$/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('^(2[0-4]\\d|25[0-5]|1\\d\\d|\\d\\d?)\\.(?1)\\.(?1)\\.(?1)$', 'gm')
const str = `1.2.3.4
91.9.9.111
0.0.0.0
121.211.233.251
255.255.255.255
121.255.255.256
256.255.255.2
999.999.999.999
`;
// Reset `lastIndex` if this regex is defined globally
// regex.lastIndex = 0;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions