uniapp的vue页面上至少得有根标签，如下，view标签。
<template>
<view></view>
</template>
<script>
</script>
<style>
</style>
如果没有根标签，如下，在手机端app编译时就会报错。
<template>
</template>
<script>
</script>
<style>
</style>
报以下错误
21:42:59.248 ERROR TypeError: Cannot set property 'mpErrors' of undefined
21:42:59.249 TypeError: Cannot set property 'mpErrors' of undefined
21:42:59.253 at Object.log (E:\softWare\HBuilderX.0.1.47.20180823-alpha.full\plugins\uniapp-cli\node_modules\@dcloudio\vue-cli-plugin-uni\packages\mpvue-template-compiler\build.js:5106:27)
21:42:59.261 at compileToWxml (E:\softWare\HBuilderX.0.1.47.20180823-alpha.full\plugins\uniapp-cli\node_modules\@dcloudio\vue-cli-plugin-uni\packages\mpvue-template-compiler\build.js:5125:21)
21:42:59.267 at compile (E:\softWare\HBuilderX.0.1.47.20180823-alpha.full\plugins\uniapp-cli\node_modules\@dcloudio\webpack-uni-mp-loader\lib\plugin\compile-to-template.js:33:9)
21:42:59.268 at Object.keys.forEach.filePath (E:\softWare\HBuilderX.0.1.47.20180823-alpha.full\plugins\uniapp-cli\node_modules\@dcloudio\webpack-uni-mp-loader\lib\plugin\generate-components-wxml.js:110:22)
21:42:59.275 at Array.forEach (<anonymous>)
21:42:59.279 at generateComponentsWxml (E:\softWare\HBuilderX.0.1.47.20180823-alpha.full\plugins\uniapp-cli\node_modules\@dcloudio\webpack-uni-mp-loader\lib\plugin\generate-components-wxml.js:72:26)
21:42:59.281 at Promise (E:\softWare\HBuilderX.0.1.47.20180823-alpha.full\plugins\uniapp-cli\node_modules\@dcloudio\webpack-uni-mp-loader\lib\plugin\index.js:128:11)
21:42:59.285 at new Promise (<anonymous>)
21:42:59.285 at compiler.hooks.emit.tapPromise.compilation (E:\softWare\HBuilderX.0.1.47.20180823-alpha.full\plugins\uniapp-cli\node_modules\@dcloudio\webpack-uni-mp-loader\lib\plugin\index.js:68:14)
21:42:59.296 at _err0 (eval at create (E:\softWare\HBuilderX.0.1.47.20180823-alpha.full\plugins\uniapp-cli\node_modules\tapable\lib\HookCodeFactory.js:32:10), <anonymous>:13:17)
21:42:59.297 at callback (E:\softWare\HBuilderX.0.1.47.20180823-alpha.full\plugins\uniapp-cli\node_modules\copy-webpack-plugin\dist\index.js:77:17)
21:42:59.303 at E:\softWare\HBuilderX.0.1.47.20180823-alpha.full\plugins\uniapp-cli\node_modules\copy-webpack-plugin\dist\index.js:118:24
21:42:59.308 at <anonymous>