vue/cli4跑單個元件測試

環境

直接跑一個vue元件，正常的命令是這樣的

• vue serve src/components/demo1.vue

輸出提示：

  Command vue serve requires a global addon to be installed.
  Please run npm i -g @vue/cli-service-global and try again.

再次安裝

  npm i -g @vue/cli-service-global