Is there a useful difference between
app.all('*', ... ) and
app.use('/', ...) in Node.JS Express?
In most cases they would work equivalently. The biggest difference is the order in which middleware would be applied:
app.all()attaches to the application's router, so it's used whenever the app.router middleware is reached (which handles all the method routes... GET, POST, etc).
NOTICE: app.router has been deprecated in express 4.x
app.use()attaches to the application's main middleware stack, so it's used in the order specified by middleware. eg, if you put it first, it will be the first thing to run. If you put it last, (after the router), it usually won't be run at all.
Usually, if you want to do something globally to all routes, app.use() is the better option. Also, it has less chance of future bugs, since express 0.4 will probably drop the implicit router (meaning, the position of the router in middleware will be more important than it is right now, since you technically don't even have to use it right now).
app.use takes only one callback function and it's meant for Middleware. Middleware usually doesn't handle request and response, (technically they can) they just process input data, and hand over it to next handler in queue.
app.all takes multiple callbacks, and meant for routing. with multiple callbacks you can filter requests and send responses. Its explained in Filters on express.js
app.all(path, [callback...], callback)
app.use only sees whether url starts with the specified path
app.use( "/product" , mymiddleware); // will match /product // will match /product/cool // will match /product/foo
app.all will match complete path
app.all( "/product" , handler); // will match /product // won't match /product/cool <-- important // won't match /product/foo <-- important app.all( "/product/*" , handler); // won't match /product <-- Important // will match /product/ // will match /product/cool // will match /product/foo