const regex = new RegExp('(?<!\\d)
(?:
(?!0000)[0-9]{4}
(?P<sep1>[-/.])?
(?:
(?:(?(sep1)0?|0)[1-9]|1[0-2]) (?P=sep1) (?:(?(sep1)0?|0)[1-9]|1[0-9]|2[0-8])
|(?:(?(sep1)0?|0)[13-9]|1[0-2]) (?P=sep1) (?:29|30)
|(?:(?(sep1)0?|0)[13578]|1[02]) (?P=sep1) (?:31)
)
|
(?:
[0-9]{2}
(?:
0[48]
|[2468][048]
|[13579][26]
)
|(?:
0[48]
|[2468][048]
|[13579][26]
)00
)
(?P<sep2>[-/.]?)
(?(sep2)0?|0)2 (?P=sep2) (?:29)
)
(?!\\d)
', 'gm')
const str = `aaa_20150229_bbb
aaa_2012-02-29_bbb
aaa_2000-02-29_bbb
aaa_20000229_bbb
2004-2-29
1696-2-29
16960229
aaa_1904229_bbb
aaa_18000229_bbb
aaa_17000229_bbb
aaa_16000229_bbb
2019-3-30
19960229
aaa_20150130_bbb
aaa_20150131_bbb
aaa_2015-04-30_bbb
aaa_20150431_bbb
2019228
2019228
201911`;
// 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