第一个视频我就出错了。

 ./src/index.js + 1 modules 224 KiB [built] [code generated]

  ./src/app.vue 39 bytes [not cacheable] [built] [code generated] [1 error]

WARNING in configuration

The 'mode' option has not been set, webpack will fallback to 'production' for this value.

Set 'mode' option to 'development' or 'production' to enable defaults for each environment.

You can also set it to 'none' to disable any default behavior. Learn more: https://webpack.js.org/configuration/mode/

ERROR in ./src/app.vue

Module build failed (from ./node_modules/vue-loader/dist/index.js):      

Error: vue-loader requires @vue/compiler-sfc to be present in the dependency tree.

    at Object.<anonymous> (D:\WebKU\VuehomeKU\Vue_loaderText\node_modules\vue-loader\dist\index.js:8:11)

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我也用了其他的方法，都还是报这个错。