const regex = /\b\d{6}(?:\d{3})?\b/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('\\b\\d{6}(?:\\d{3})?\\b', 'gm')
const str = `ID 123 - it should not meet the regext as it is 3 digits
ID 1234 - it should not meet the regext as it is 4 digits
ID 12345 - it should not meet the regext as it is 5 digits
ID 123456 - it should meet the regex it is 6 digits <==========
ID 1234567 - it should not meet the regext as it is 7 digits
ID 12345678 - it should not meet the regext as it is 8 digits
ID 123456789 - it should meet the regext as it is 9 digits <==========
ID 1234567890 - it should not meet the regext as it is 10 digits
ID 12345678901 - it should not meet the regext as it is 11 digits`;
// 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