const regex = /^([1-9]\d*)-(0[1-9]|1[0-2])-(0?[1-9]|[1-2]\d|3[0-2])(?:\x20([01][0-9]|2[0-3]):([0-5]\d):([0-5]\d)(\.\d+)?)?$/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('^([1-9]\\d*)-(0[1-9]|1[0-2])-(0?[1-9]|[1-2]\\d|3[0-2])(?:\\x20([01][0-9]|2[0-3]):([0-5]\\d):([0-5]\\d)(\\.\\d+)?)?$', 'gm')
const str = `2015-03-32 07:00:00
2015-05-15 12:00:54.02911`;
const subst = `year: $1, month: $2, day: $3, hours: $4, minutes: $5, seconds: $6$7`;
// The substituted value will be contained in the result variable
const result = str.replace(regex, subst);
console.log('Substitution result: ', result);
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