This is a specification draft for the legacy (deprecated) RegExp features in JavaScript, i.e., static properties of the constructor like RegExp.$1 as well as the RegExp.prototype.compile method. This ...
See details in the proposal. Capturing groups in JS regexes until recent supported only numbered-matching. For example, given /(\d{4})-(\d{2})-(\d{2})/ that matches a date, one cannot be sure which ...