## Error: Couldn't find preset "env" relative to directory 这是因为`.babelrc`文件里的配置 ``` ["env", { "modules": false, "targets": { "browsers": ["> 1%", "last 2 versions", "not ie <= 8"] } }], ``` 这里配置的`env`需要`babel-preset-env`这个模块 执行 ``` cnpm i babel-preset-env --save-dev ```