Do not match certain words as parameters with path-to-regexp

[Milutin-P]

I have a route /:parameter and if someone pings that route I should serve him certain page (React App)
So what I need is some kind of regexp that wont match certain words...

Regular expression should be ^(?!.*(foobar1|\/foobar2)).*$

https://pshrmn.github.io/route-tester/#/ I've used this tool for testing and entered various combinations, such as /parameter(?!.*(foobar1|\/foobar2)) but no luck...

So test case should be

if path is /foobar3 it should return page
if path is /foobar2 or /foobar3 it should return null

[tigt]

Does “the best regex trick” work for your needs? I think it would express your example as /(?:foobar2|foobar3|(foobar1))/, but I admit I couldn’t figure out how to translate it into a form that the linked route-tester page was happy with.

[juanmagalhaes]

+1 here. I'm facing the same issue right now.

[blakeembrey]

If someone wants to propose expanding the existing syntax to support this, I'm happy to review.

Otherwise I'd suggest maybe filing a ticket with the libraries using this package to support this feature. It's definitely easier than trying to construct a negative regex. For example, in something like Express you can have middleware that runs and write a line of code that says parameter !== 'foobar1' to skip the middleware on that condition.

[Seunfola]

I think you should define the parameters for the dynamic route then use the logic to return the page

const isExcluded = /^(?!foobar1$|foobar2$).+/.test(parameter);

if (!isExcluded) {
return null;
}

[blakeembrey]

Closing this out as V8 does not support custom regexes, and I would recommend that libraries provide an ability to exclude paths rather than require complex regexes. However, in versions prior to V8 you can achieve this with a negative lookahead, something like /:foo((?!foobar2$|foobar3$)[^/]+), where you want to match a parameter that doesn't equal foobar2 or foobar3.