Looks like you need to escape { and } but in JS-flavored regex you do not

[incompl]

Looks like you need to escape { and } but in JS-flavored regex you do not

[javallone]

I'm committing a fix for this.

From my experiments in the browser, you are allowed to have unescaped "{" and "}" characters so long as they don't look like a specification for a repetition (so you can't do "{1}", "{1,2}", etc).