app.use('*') vs app.use('/*')

[dbzx10299]

I have been learning express and I was looking at the vite ssr playground and I came across the asterisk used by itself.

Surprisingly I have not been able to find any info on this anywhere else.

My question is what is

app.use('*', (req, res, next) => {
  // ...
})

and if it is different from just using

app.use((req, res, next) => {
  // ...
})

Lastly is this doing anything different, or are these all ways to do the same thing?

app.use('/*', (req, res, next) => {
  // ...
})

[ichenglin]

The app.use method is one of the express middlewares, which differ from others (such as app.get() and app.put())
that it was triggered whenever the route path matches, no matter the type of the request.

Additionally, the three middleware routes you provided would sure behave the same way.
Routes all begin at the root level (/), so wildcard routes * and /* match all routes;
while if you don't pass in any routes at all, it also matches all by default.

For further details on how to use express middlewares,
I recommend you to check out the official documentation.

[dbzx10299]

I have read those docs over already but I was having a hard time understanding why the same thing would be written in different ways.
Is there any convention that is used? I am wondering because they do the same thing but I‘ve seen app.use('/*') and app.use('*') in the same project.

[dougwilson]

The convention is to use only what you need. The * will actually create a capture group that is available in req.params. If you don't need that capture group, I would recommend not asking for it in the route to save some time and memory. Many people copy and paste code, so that's probably why there are different things in the same project that all seem to do the same thing 🤷‍♂️ . Only person who wrote it there could tell us why they choose a particular method of doing it.

[dbzx10299]

Got it. Thanks a lot

[dougwilson]

No problem. Typically app.use('/*', ...) is not very useful as I never see anyone who does that use req.params in their handler, so just a capture group was made for no reason, lol.