配置babel时，配置完.babelrc文件，运行报错：

错误日志：

Error: Multiple configuration files found. Please remove one:

• package.json
• /Users/maomao/Documents/demo/h5/mm_webpack/.babelrc

ERROR in ./src/aaa.js
Module build failed (from ./node_modules/babel-loader/lib/index.js):
Error: Multiple configuration files found. Please remove one:
 - package.json
 - /Users/maomao/Documents/demo/h5/mm_webpack/.babelrc
from /Users/maomao/Documents/demo/h5/mm_webpack
    at /Users/maomao/Documents/demo/h5/mm_webpack/node_modules/@babel/core/lib/config/files/configuration.js:136:13

原因：

安装babel时package.json文件中自动生成了babel相关的配置:

  "babel": {
    "presets": [
      "react-app"
    ]
  },

但是.babelrc文件中也有一份配置：

{
    "presets": [
        "@babel/preset-env"
    ],
    "plugins": [
        "@babel/plugin-transform-runtime",
        "@babel/plugin-proposal-class-properties"
    ]
}

所以保留一份就可以了。

解决办法：

删除package.json中的配置。