TypeError: Router.use() requires a middleware function but got a Null

[katoumorisan]

some errors come out when I have done proceeding the last procedure of the steps as your blog says:
`
[root@webrtc-server webrtc_server_node]# node server.js
/root/webrtc_server_node/node_modules/express/lib/router/index.js:458
throw new TypeError('Router.use() requires a middleware function but got a ' + gettype(fn))
^

TypeError: Router.use() requires a middleware function but got a Null
at Function.use (/root/webrtc_server_node/node_modules/express/lib/router/index.js:458:13)
at Function. (/root/webrtc_server_node/node_modules/express/lib/application.js:220:21)
at Array.forEach ()
at Function.use (/root/webrtc_server_node/node_modules/express/lib/application.js:217:7)
at Object. (/root/webrtc_server_node/server.js:9:5)
at Module._compile (internal/modules/cjs/loader.js:778:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:10)
at Module.load (internal/modules/cjs/loader.js:653:32)
at tryModuleLoad (internal/modules/cjs/loader.js:593:12)
at Function.Module._load (internal/modules/cjs/loader.js:585:3)
`

i got this error too.

[ddssingsong]

It may be that the version of node is too low

[wsdydeni]

app.use([path], function(request, response, next){})

app.use(express.static(path.join(__dirname, '/')));

only set static path, no funcation

[hotsmile]

同样的问题，my node version is v16.19.0