Error: listen EADDRINUSE: address already in use 0.0.0.0:8080

[hoboy0313]

Version

4.0.4

Reproduction link

https://github.com/hotpotLeo/mobile-vue-wrapper

Environment info

Error: listen EADDRINUSE: address already in use 0.0.0.0:8080
    at Server.setupListenHandle [as _listen2] (net.js:1279:14)
    at listenInCluster (net.js:1327:12)
    at doListen (net.js:1460:7)
    at process._tickCallback (internal/process/next_tick.js:63:19)
    at Function.Module.runMain (internal/modules/cjs/loader.js:832:11)
    at startup (internal/bootstrap/node.js:283:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)
Emitted 'error' event at:
    at emitErrorNT (net.js:1306:8)
    at process._tickCallback (internal/process/next_tick.js:63:19)
    [... lines matching original stack trace ...]
    at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)
error Command failed with exit code 1. 

Steps to reproduce

1. git clone
2. yarn
3. yarn dev

What is expected?

I'm no use the port before i run the program, even I change the port with 8888, it's still happen.

What is actually happening?

The error should not be happen

[haoqunjiang]

yarn serve | npm run serve

You used the pipe operator |, which will first run yarn serve and then pass the output of this command as stdin to the second command npm run serve. That means you are running two servers simultaneously, of course there will be an error.