Proposal to add the word boundary assertions \b{w} to regular expressions in ECMAScript with the u flag, to match Unicode extended grapheme cluster boundaries, as described in Unicode Technical Standard #18.
Characters that are matched by the short-hand character class \w are the characters that are treated as word characters by word boundaries. So /na\b/u.test('naïve') returns true. And yet nobody would normally consider in Unicode-aware contexts that there are two word boundaries in the middle of naïve or fiancée.
There currently is no way to access these Unicode character properties natively in ECMAScript regular expressions. This makes it painful for developers to support full Unicode in their regular expressions.
We propose the addition of Unicode word boundaries of the form \b{w} and \B{W} available in regular expressions that have the u flag set. With this feature, the above regular expression could be written as:
/na\b{w}/u.test('naïve')
// → false