const regex = /^(?:\d{1,3}(,\d{3})*|\d+|\d{2}(?:,\d{2})*,\d{3})(?:\.\d+)?$/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('^(?:\\d{1,3}(,\\d{3})*|\\d+|\\d{2}(?:,\\d{2})*,\\d{3})(?:\\.\\d+)?$', 'gm')
const str = `--valid--
1000
1000.12
1,000
1,000.12
10,000
10,000.12
10,000,000
10,000,000.12
10,00,00,000
10,00,00,000.12
--invalid--
100,
1000.
1000.12,
1000.12.34
1000,.12
,1000
,1000.12
1,,000
1,,00.12
.12
,,,,,`;
// 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