.env 文件详解

VUE_APP_ENV=dev
// 只支持：VUE_APP_ 开头，比如设置其它变量 VUE_APP_NAME=stark

  "scripts": {
    "start": "npm run dev",
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build",
    "dev": "vue-cli-service serve --mode dev",
    "test": "vue-cli-service build --mode test",
    "pre": "vue-cli-service build --mode pre",
    "prod": "vue-cli-service build --mode prod",
    "lint": "vue-cli-service lint"
  },

npm start // 默认dev
npm run test // test 环境
...
以此类推

通过 process.env 获取设置的变量
比如：console.log(‘当前的环境是‘,process.env.VUE_APP_ENV)