Is there a way to use ungreedy matching in JavaScript for regular expressions?

Question

I wonder if there is a way to use ungreedy matching in JavaScript? I tried the U modifer, but it doesn't seem to work.

I want to write a small BBCode parser in JavaScript, but without ungreedy matching it isn't possible (at least as far as I see it) to do something like this:

'[b]one[/b] two [b]three[/b]'.replace( /\[b\](.*)\[\/b\]/, '<b>$1</b>' );

But such a replacement would be nice since there is no need to check for HTML validity then. Unclosed markups will stay simple text.

Cormier

Answer 1

You can use ? after * or + to make it ungreedy, e.g. (.*?)

Corallite

Incredible, but it just works! Thanks. in other enviroments, the flag /u (ungreedy) can be used. But for javascript methods is not available (with exception of nodejs methods, i think) – Stab

Please could you try to explain the logic behind this trick ? – Lack

@Lack there isn't a logic behind this trick to explain. * and *? are two different quantifiers. * is the greedy quantifier (match zero to unlimited times as many times as possible) *? is the lazy quantifier (match zero to unlimited times as few times as possible). Fun fact: Using the flag U (Ungreedy) seems to revers the meaning. However the flag isn't supported by js and the lowercase u is the unicode-flag. – Grisette

Answer 2

I'm late, but I'll post the regex anyway.

'[b]one[/b] two [b]three[/b]'.replace( /\[b\](.+?)\[\/b\]/g, '<b>$1</b>' );

Welcome