const regex = /^(?:\d{2,3},)+(\d{2,3}),?$|^\d{2,3}$/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('^(?:\\d{2,3},)+(\\d{2,3}),?$|^\\d{2,3}$', 'gm')
const str = `//pass
12,123,56,567,789,11
12,123,56,567,789,11,
12
123
//fail
12,123,56,567,789,11a
a12,123,56,567,789,11
12,123,56,567,789,1
1,123,56,567,789,11
1234,123,56,567,789,11
12,123,56,567,789,1123
1
1234`;
// 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