vue-cli 配合webpack4 报错 Cannot assign to read only property 'exports' of object '#<Object>' 解决方法

主要是export和import共用了导致不兼容引起的错误，要解决这个问题有两个方法

找到.babelrc 文件，在插件位置  plugins 给一个空的数组 

{
  "presets": [
    ["env", {
      "modules": false,
      "targets": {
        "browsers": ["> 1%", "last 2 versions", "not ie <= 8"]
      }
    }],
    "stage-2"
  ],
  "plugins": [],
  "env": {
    "test": {
      "presets": ["env", "stage-2"],
      "plugins": ["transform-vue-jsx", "istanbul"]
    }
  }
}

　第二种方法是 在同样的文件里面加上一句 

"plugins": ["transform-es2015-modules-commonjs"]

{
  "presets": [
    ["env", {
      "modules": false,
      "targets": {
        "browsers": ["> 1%", "last 2 versions", "not ie <= 8"]
      }
    }],
    "stage-2"
  ],
  "plugins": ["transform-vue-jsx", "transform-runtime","transform-es2015-modules-commonjs"],
  "env": {
    "test": {
      "presets": ["env", "stage-2"],
      "plugins": ["transform-vue-jsx", "istanbul"]
    }
  }
}

　　推荐使用第二种