Getting error(Uncaught SyntaxError: Unexpected token '<') after "npm run serve"

[Somnus007]

Version

4.3.1

Reproduction link

https://github.com/Somnus007/vue-demo

Environment info

Environment Info:

  System:
    OS: macOS 10.15.4
    CPU: (4) x64 Intel(R) Core(TM) i5-7360U CPU @ 2.30GHz
  Binaries:
    Node: 12.16.3 - /usr/local/bin/node
    Yarn: 1.15.2 - /usr/local/bin/yarn
    npm: 6.14.5 - /usr/local/bin/npm
  Browsers:
    Chrome: 83.0.4103.61
    Edge: 80.0.361.111
    Firefox: 76.0.1
    Safari: 13.1
  npmPackages:
    @vue/babel-helper-vue-jsx-merge-props:  1.0.0 
    @vue/babel-plugin-transform-vue-jsx:  1.1.2 
    @vue/babel-preset-app:  4.3.1 
    @vue/babel-preset-jsx:  1.1.2 
    @vue/babel-sugar-functional-vue:  1.1.2 
    @vue/babel-sugar-inject-h:  1.1.2 
    @vue/babel-sugar-v-model:  1.1.2 
    @vue/babel-sugar-v-on:  1.1.2 
    @vue/cli-overlay:  4.3.1 
    @vue/cli-plugin-babel: ~4.3.0 => 4.3.1 
    @vue/cli-plugin-eslint: ~4.3.0 => 4.3.1 
    @vue/cli-plugin-router:  4.3.1 
    @vue/cli-plugin-vuex:  4.3.1 
    @vue/cli-service: ~4.3.0 => 4.3.1 
    @vue/cli-shared-utils:  4.3.1 
    @vue/component-compiler-utils:  3.1.2 
    @vue/preload-webpack-plugin:  1.1.1 
    @vue/web-component-wrapper:  1.2.0 
    eslint-plugin-vue: ^6.2.2 => 6.2.2 
    vue: ^2.6.11 => 2.6.11 
    vue-eslint-parser:  7.1.0 
    vue-hot-reload-api:  2.3.4 
    vue-loader:  15.9.2 
    vue-style-loader:  4.1.2 
    vue-template-compiler: ^2.6.11 => 2.6.11 
    vue-template-es2015-compiler:  1.9.1 
  npmGlobalPackages:
    @vue/cli: 4.3.1

Steps to reproduce

• vue create vue-demo
• cd vue-demo
• npm run serve

What is expected?

I can access to the home page with a hello world content

What is actually happening?

I got a blank page, and there is a error (Uncaught SyntaxError: Unexpected token '<') on broswer console

---

I created a demo by using @vue-cli 4.3.1 and have not changed any code yet. But I got a blank page after run "npm run serve"

[haoqunjiang]

I'm sorry but I can't reproduce the error. Do you have a more detailed error log? What's the exact error stack and from which file did it throw?

[Somnus007]

[haoqunjiang]

npm run serve won't serve a production service worker, neither does it come with hashed assets files.
It must be due to the incorrect service worker caches brought by other projects that were previously served at localhost:8080.

So, please clear your browser service worker cache (Chrome Dev Tools -> Application -> Clear Storage -> Clear site data)

[Somnus007]

@sodatea Yes, that's it. Everything is ok now, thanks

[Pryme8]

I am getting the same error, I have followed all the steps with clearing the cache. Making sure you have the correct version of cli installed etc. Have gone through every stackoverflow suggestion and all the stuff I can find on git about it still to no avail.

My app runs correctly on the first npm run serve but fails on the first refresh or even a hard reload with the
Uncaught SyntaxError: Unexpected token '<' Error

I am running Windows 10 and here are all my dependencys

"dependencies": {
    "@babylonjs/core": "^4.2.0",
    "@babylonjs/materials": "^4.2.0",
    "@babylonjs/gui": "^4.2.0",
    "core-js": "^3.9.0",
    "vee-validate": "^3.4.5",
    "vue": "^2.6.12",
    "vue-router": "^3.5.1",
    "vuetify": "^2.4.4",
    "vuex": "^3.6.2"
  },
  "devDependencies": {
    "@mdi/font": "^5.9.55",
    "@vue/cli-plugin-babel": "~4.5.11",
    "@vue/cli-plugin-eslint": "~4.5.11",
    "@vue/cli-plugin-router": "^4.5.11",
    "@vue/cli-plugin-vuex": "^4.5.11",
    "@vue/cli-service": "~4.5.11",
    "babel-eslint": "^10.0.3",
    "eslint": "^7.20.0",
    "eslint-plugin-vue": "^7.6.0",
    "eslint-plugin-vuetify": "^1.0.0-beta.8",
    "sass": "^1.32.8",
    "sass-loader": "^10.1.1",
    "vue-cli-plugin-vuetify": "~2.1.0",
    "vue-loader": "^15.9.6",
    "vue-template-compiler": "^2.6.12",
    "vuetify-loader": "^1.7.2"
  }

Is there maybe a conflict in my versions? What would be another route to try?
Sorry for the thread necro.