const regex = /(20\d{2})(\d{2})(\d{2})/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('(20\\d{2})(\\d{2})(\\d{2})', 'gm')
const str = `aaa_20150229_bbb
aaa_20120229_bbb
aaa_20000229_bbb
aaa_19000229_bbb
aaa_18000229_bbb
aaa_17000229_bbb
aaa_16000229_bbb
aaa_20150130_bbb
aaa_20150131_bbb
aaa_20150430_bbb
aaa_20150431_bbb`;
// 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