vue项目npm run dev报错

使用cnpm install也不行。

 ERROR  Failed to compile with 1 errors                                                                                                                                                                           11:16:55
 error  in ./src/App.vue

Module build failed: Error: ENOENT: no such file or directory, scandir 'E:\BaiduNetdiskDownload\mmm20190430\node_modules\node-sass\vendor'
    at Object.readdirSync (fs.js:785:3)
    at Object.getInstalledBinaries (E:\BaiduNetdiskDownload\mmm20190430\node_modules\node-sass\lib\extensions.js:130:13)
    at foundBinariesList (E:\BaiduNetdiskDownload\mmm20190430\node_modules\node-sass\lib\errors.js:20:15)
    at foundBinaries (E:\BaiduNetdiskDownload\mmm20190430\node_modules\node-sass\lib\errors.js:15:5)
    at Object.module.exports.missingBinary (E:\BaiduNetdiskDownload\mmm20190430\node_modules\node-sass\lib\errors.js:45:5)
    at module.exports (E:\BaiduNetdiskDownload\mmm20190430\node_modules\node-sass\lib\binding.js:15:30)
    at Object.<anonymous> (E:\BaiduNetdiskDownload\mmm20190430\node_modules\node-sass\lib\index.js:14:35)
    at Module._compile (internal/modules/cjs/loader.js:701:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:712:10)
    at Module.load (internal/modules/cjs/loader.js:600:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:539:12)
    at Function.Module._load (internal/modules/cjs/loader.js:531:3)
    at Module.require (internal/modules/cjs/loader.js:637:17)
    at require (internal/modules/cjs/helpers.js:22:18)
    at Object.sassLoader (E:\BaiduNetdiskDownload\mmm20190430\node_modules\sass-loader\lib\loader.js:46:72)

 @ ./node_modules/vue-style-loader!./node_modules/css-loader?{"sourceMap":true}!./node_modules/vue-loader/lib/style-compiler?{"vue":true,"id":"data-v-7ba5bd90","scoped":false,"hasInlineConfig":false}!./node_modules/sass-loader/lib/loader.js?{"sourceMap":true}!./node_modules/vue-loader/lib/selector.js?type=styles&index=0!./src/App.vue 4:14-359 13:3-17:5 14:22-367
 @ ./src/App.vue
 @ ./src/main.js
 @ multi (webpack)-dev-server/client?http://0.0.0.0:8098 webpack/hot/dev-server babel-polyfill ./src/main.js

执行cnpm install node-sass --save;之后，再执行npm run dev终于成功了。

1、cnpm install
2、cnpm install sass-loader --save;
3、cnpm install node-sass --save;
4、cnpm install babel-polyfill --save-dev  //解决浏览器对es6语法的支持
5、cnpm install es6-promise --save-dev //解决浏览器对es6语法的支持
6、npm run dev

注1：浏览器对es6语法的支持需修改webpack.base.conf.js：
module.exports = {
  context: path.resolve(__dirname, '../'),
  entry: {
    app: ['babel-polyfill', './src/main.js'],/* 用这个代替下面的 */
        /*entry: {
    app: './src/main.js'
        },*/
  },
注2：浏览器对es6语法的支持需修改main.js增加：
import 'babel-polyfill';
import promise from 'es6-promise';
promise.polyfill();