Syntax Error: Error: Duplicate plugin/preset detected.， 执行npm run dev:mp-weixin的时候报错了

是一个vue-cli项目，报错如下

开始编译当前项目至 mp-weixin 平台...

ERROR Failed to compile with 2 errors 15:13:18

error in ./src/main.js

Syntax Error: Error: Duplicate plugin/preset detected.
If you'd like to use two separate instances of a plugin,
they need separate names, e.g.

plugins: [
['some-plugin', {}],
['some-plugin', {}, 'some unique name'],
]

Duplicates detected are:
[
{
"alias": "D:\www\weixin_ppx2\node_modules\@dcloudio\webpack-uni-mp-loader\lib\babel\plugin-create-app.js",
"dirname": "D:\www\weixin_ppx2",
"ownPass": false,
"file": {
"request": "D:\www\weixin_ppx2\node_modules\@dcloudio\webpack-uni-mp-loader\lib\babel\plugin-create-app.js",
"resolved": "D:\www\weixin_ppx2\node_modules\@dcloudio\webpack-uni-mp-loader\lib\babel\plugin-create-app.js"
}
},
{
"alias": "D:\www\weixin_ppx2\node_modules\@dcloudio\webpack-uni-mp-loader\lib\babel\plugin-create-app.js",
"dirname": "D:\www\weixin_ppx2",
"ownPass": false,
"file": {
"request": "D:\www\weixin_ppx2\node_modules\@dcloudio\webpack-uni-mp-loader\lib\babel\plugin-create-app.js",
"resolved": "D:\www\weixin_ppx2\node_modules\@dcloudio\webpack-uni-mp-loader\lib\babel\plugin-create-app.js"
}
}
]
at createDescriptors.next (<anonymous>)
at createPluginDescriptors.next (<anonymous>)
at Generator.next (<anonymous>)
at Generator.next (<anonymous>)
at Generator.next (<anonymous>)
at cachedFunction.next (<anonymous>)
at mergeChainOpts.next (<anonymous>)
at chainWalker.next (<anonymous>)
at buildRootChain.next (<anonymous>)
at loadPrivatePartialConfig.next (<anonymous>)
at loadPartialConfig.next (<anonymous>)
at new Promise (<anonymous>)
at Generator.next (<anonymous>)
at new Promise (<anonymous>)

error in ./src/pages.json

Syntax Error: Unexpected end of JSON input
at JSON.parse (<anonymous>)

ERROR Build failed with errors.