RegExp.prototype.sticky

The sticky accessor property of RegExp instances returns whether or not the y flag is used with this regular expression.

RegExp.prototype.sticky has the value true if the y flag was used; otherwise, false. The y flag indicates that the regex attempts to match the target string only from the index indicated by the lastIndex property (and unlike a global regex, does not attempt to match from any later indexes).

The set accessor of sticky is undefined. You cannot change this property directly.

They start matching at lastIndex. When the match succeeds, lastIndex is advanced to the end of the match. When lastIndex is out of bounds of the currently matched string, lastIndex is reset to 0.