'vue-cli-service serve --port' does not work as advertised

[captainrdubb]

Version

3.10.0

Environment info

 System:
    OS: Linux 4.15 Ubuntu 18.04.3 LTS (Bionic Beaver)
    CPU: (12) x64 AMD Ryzen 5 1600X Six-Core Processor
  Binaries:
    Node: 10.14.1 - ~/.nvm/versions/node/v10.14.1/bin/node
    Yarn: 1.15.2 - ~/.yarn/bin/yarn
    npm: 6.4.1 - ~/.nvm/versions/node/v10.14.1/bin/npm
  Browsers:
    Chrome: 76.0.3809.100
    Firefox: 68.0.2
  npmPackages:
    @vue/babel-helper-vue-jsx-merge-props:  1.0.0 
    @vue/babel-plugin-transform-vue-jsx:  1.0.0 
    @vue/babel-preset-app:  3.10.0 
    @vue/babel-preset-jsx:  1.1.0 
    @vue/babel-sugar-functional-vue:  1.0.0 
    @vue/babel-sugar-inject-h:  1.0.0 
    @vue/babel-sugar-v-model:  1.0.0 
    @vue/babel-sugar-v-on:  1.1.0 
    @vue/cli-overlay:  3.10.0 
    @vue/cli-plugin-babel: ^3.10.0 => 3.10.0 
    @vue/cli-plugin-typescript: ^3.10.0 => 3.10.0 
    @vue/cli-plugin-unit-mocha: ^3.10.0 => 3.10.0 
    @vue/cli-service: ^3.10.0 => 3.10.0 
    @vue/cli-shared-utils:  3.10.0 
    @vue/component-compiler-utils:  2.6.0 (3.0.0)
    @vue/preload-webpack-plugin:  1.1.1 
    @vue/test-utils: 1.0.0-beta.29 => 1.0.0-beta.29 
    @vue/web-component-wrapper:  1.2.0 
    typescript: ^3.4.3 => 3.5.3 
    vue: ^2.6.10 => 2.6.10 
    vue-class-component: ^7.0.2 => 7.1.0 
    vue-hot-reload-api:  2.3.3 
    vue-loader:  15.7.1 
    vue-property-decorator: ^8.1.0 => 8.2.1 
    vue-style-loader:  4.1.2 
    vue-template-compiler: ^2.6.10 => 2.6.10 
    vue-template-es2015-compiler:  1.9.1 
    vuex: ^3.0.1 => 3.1.1 
  npmGlobalPackages:
    @vue/cli: 3.10.0

Steps to reproduce

run 'npm serve --port ' or 'vue-cli-service serve --port ' in terminal.

What is expected?

i expect the server to listen on the declared port argument or print an error

What is actually happening?

a random port is selected between the declared port argument and portfinder's default max safe port number 40000

---

i found the code in node_modules/@vue/cli-service/lib/commands/serve.js leveraging portfinder line 80 & 81. it appears portfinder.basePort is set to the port argument, then portfinder.getPortPromise is called, which returns a random port number.

[hhhpw]

I have same question.
version: 3.10.0
I want change the port of project. but it not works.
vue.config.js module.exports = { devServer: { port: 8091, open: true }, lintOnSave: false };
cll --port also not works.

[mpromonet]

Hi,
This problem is reported in https://stackoverflow.com/questions/57536785/vue-npm-run-serve-starts-on-random-port and I submit the PR to avoid this problem #4451
This PR change a little the behaviour when the port is used, before the next port was use with this modification it will failed.
Best Regards,
Michel.

[vkaracic]

Was just about to report the same. I'm using 4.0.0-beta.3 release and have the same issue.

  devServer: {
    port: 8080
  },

doesn't do anything, the port is still a random one.

[imaginarny]

Well, yes. I spent last night trying all 4 methods I could think of but neither worked.

• Writing port argument in serve script in package.json
  "serve": "vue-cli-service serve --port 8080"
• Using .env, .env.*, .env.*.local files with variable
  PORT=8080
• Using vue.config.js
  devServer: { port: 8080 }
• By passing an argument in cli command e.g.
  npm run serve -- --port 8080 or npx vue-cli-service serve --port 8080

[mpromonet]

Hi @imaginarny @vkaracic ,
The PR is not merged, you could try patching node_modules/@vue/cli-service/lib/commands/serve.js

A way to workaround the problem is to install old portfinder with:

   npm install portfinder@1.0.21

Best Regards,
Michel.

[XLearner]

Yeah. The previous two days, it still worked. But today, I create a new project, vue.config.js is not worked. What happened.

[ThibaultVlacich]

Yeah. The previous two days, it still worked. But today, I create a new project, vue.config.js is not worked. What happened.

https://github.com/http-party/node-portfinder/ released a breaking change as a minor bugfix release, that's what happened...

[designbydc]

Yes, same problem here. The vue.config.js in my project is loading fine but the port 8080 or other port number will not be replaced

[pravosleva]

--port option does not work.

node 10.16.3
yarn 1.17.3
@vue/cli@3.10.0 (and @vue/cli@4.0.0-beta.1 too)

Or vue-cli-service serve --port 3000 in package.json script like this:

...But not specified port will be used. Could anybody please help me? )

• And also, tcp port 3000 was killed in dev.sh before start by $ yarn --cwd ./frontend serve.
• All deps installed: $ rm -rf ./node_modules && yarn install in /frontend
• Then I tried this: @vue/cli@4.0.0-beta.1 installed globally. But not specified port will be used again (screen below).

[pravosleva]

@bokub Why should I have to use vue serve when vue-cli asked me what gonna be used yarn or npm? yarn was selected already.
/frontend directory was created by $ vue create frontend as project with base files pack. In settings i selected yarn to use. So project could be started by $ yarn serve.

[pravosleva]

For example $ vue serve --port 3000 from terminal: