found an issue when run script 'ng serve'

[839928622]

ERROR in ./src/styles.scss (./node_modules/@angular-devkit/build-angular/src/angular-cli-files/plugins/raw-css-loader.js!./node_modules/postcss-loader/src??embedded!./node_modules/sass-loader/lib/loader.js??ref--14-3!./src/styles.scss)
Module build failed (from ./node_modules/sass-loader/lib/loader.js):
Error: Cannot find module 'node-sass'
Require stack:

• H:\Github\angular-pro-sidebar\node_modules\sass-loader\lib\loader.js
• H:\Github\angular-pro-sidebar\node_modules\loader-runner\lib\loadLoader.js
• H:\Github\angular-pro-sidebar\node_modules\loader-runner\lib\LoaderRunner.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\NormalModule.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\NormalModuleFactory.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\Compiler.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\webpack.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\build-webpack\src\webpack\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\build-webpack\src\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\build-angular\src\dev-server\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\architect\src\architect.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\architect\src\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\models\architect-command.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\commands\build-impl.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\schematics\tools\export-ref.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\schematics\tools\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\utilities\json-schema.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\models\command-runner.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\lib\cli\index.js
• C:\Users\Leo\AppData\Roaming\npm\node_modules@angular\cli\lib\init.js
• C:\Users\Leo\AppData\Roaming\npm\node_modules@angular\cli\bin\ng
  at Function.Module._resolveFilename (internal/modules/cjs/loader.js:793:17)
  at Function.Module._load (internal/modules/cjs/loader.js:686:27)
  at Module.require (internal/modules/cjs/loader.js:848:19)
  at require (internal/modules/cjs/helpers.js:74:18)
  at Object.sassLoader (H:\Github\angular-pro-sidebar\node_modules\sass-loader\lib\loader.js:46:72)
  ERROR in ./src/app/app.component.scss
  Module build failed (from ./node_modules/sass-loader/lib/loader.js):
  Error: Cannot find module 'node-sass'
  Require stack:
• H:\Github\angular-pro-sidebar\node_modules\sass-loader\lib\loader.js
• H:\Github\angular-pro-sidebar\node_modules\loader-runner\lib\loadLoader.js
• H:\Github\angular-pro-sidebar\node_modules\loader-runner\lib\LoaderRunner.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\NormalModule.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\NormalModuleFactory.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\Compiler.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\webpack.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\build-webpack\src\webpack\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\build-webpack\src\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\build-angular\src\dev-server\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\architect\src\architect.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\architect\src\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\models\architect-command.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\commands\build-impl.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\schematics\tools\export-ref.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\schematics\tools\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\utilities\json-schema.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\models\command-runner.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\lib\cli\index.js
• C:\Users\Leo\AppData\Roaming\npm\node_modules@angular\cli\lib\init.js
• C:\Users\Leo\AppData\Roaming\npm\node_modules@angular\cli\bin\ng
  at Function.Module._resolveFilename (internal/modules/cjs/loader.js:793:17)
  at Function.Module._load (internal/modules/cjs/loader.js:686:27)
  at Module.require (internal/modules/cjs/loader.js:848:19)
  at require (internal/modules/cjs/helpers.js:74:18)
  at Object.sassLoader (H:\Github\angular-pro-sidebar\node_modules\sass-loader\lib\loader.js:46:72)
  ERROR in ./src/app/sidebar/sidebar.component.scss
  Module build failed (from ./node_modules/sass-loader/lib/loader.js):
  Error: Cannot find module 'node-sass'
  Require stack:
• H:\Github\angular-pro-sidebar\node_modules\sass-loader\lib\loader.js
• H:\Github\angular-pro-sidebar\node_modules\loader-runner\lib\loadLoader.js
• H:\Github\angular-pro-sidebar\node_modules\loader-runner\lib\LoaderRunner.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\NormalModule.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\NormalModuleFactory.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\Compiler.js
• H:\Github\angular-pro-sidebar\node_modules\webpack\lib\webpack.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\build-webpack\src\webpack\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\build-webpack\src\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\build-angular\src\dev-server\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\architect\src\architect.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\architect\src\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\models\architect-command.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\commands\build-impl.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\schematics\tools\export-ref.js
• H:\Github\angular-pro-sidebar\node_modules@angular-devkit\schematics\tools\index.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\utilities\json-schema.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\models\command-runner.js
• H:\Github\angular-pro-sidebar\node_modules@angular\cli\lib\cli\index.js
• C:\Users\Leo\AppData\Roaming\npm\node_modules@angular\cli\lib\init.js
• C:\Users\Leo\AppData\Roaming\npm\node_modules@angular\cli\bin\ng
  at Function.Module._resolveFilename (internal/modules/cjs/loader.js:793:17)
  at Function.Module._load (internal/modules/cjs/loader.js:686:27)
  at Module.require (internal/modules/cjs/loader.js:848:19)
  at require (internal/modules/cjs/helpers.js:74:18)
  at Object.sassLoader (H:\Github\angular-pro-sidebar\node_modules\sass-loader\lib\loader.js:46:72)

and then I run 'npm install sass-loader node-sass webpack --save-dev'， it showed:
ERROR in ./src/styles.scss (./node_modules/@angular-devkit/build-angular/src/angular-cli-files/plugins/raw-css-loader.js!./node_modules/postcss-loader/src??embedded!./node_modules/sass-loader/dist/cjs.js??ref--14-3!./src/styles.scss)
Module build failed (from ./node_modules/sass-loader/dist/cjs.js):
ValidationError: Invalid options object. Sass Loader has been initialized using an options object that does not match the API schema.

• options has an unknown property 'includePaths'. These properties are valid:
  object { implementation?, sassOptions?, prependData?, sourceMap?, webpackImporter? }
  at validate (H:\Github\angular-pro-sidebar\node_modules\sass-loader\node_modules\schema-utils\dist\validate.js:85:11)
  at Object.loader (H:\Github\angular-pro-sidebar\node_modules\sass-loader\dist\index.js:36:28)
  ERROR in ./src/app/app.component.scss
  Module build failed (from ./node_modules/sass-loader/dist/cjs.js):
  ValidationError: Invalid options object. Sass Loader has been initialized using an options object that does not match the API schema.
• options has an unknown property 'includePaths'. These properties are valid:
  object { implementation?, sassOptions?, prependData?, sourceMap?, webpackImporter? }
  at validate (H:\Github\angular-pro-sidebar\node_modules\sass-loader\node_modules\schema-utils\dist\validate.js:85:11)
  at Object.loader (H:\Github\angular-pro-sidebar\node_modules\sass-loader\dist\index.js:36:28)
  ERROR in ./src/app/sidebar/sidebar.component.scss
  Module build failed (from ./node_modules/sass-loader/dist/cjs.js):
  ValidationError: Invalid options object. Sass Loader has been initialized using an options object that does not match the API schema.
• options has an unknown property 'includePaths'. These properties are valid:
  object { implementation?, sassOptions?, prependData?, sourceMap?, webpackImporter? }
  at validate (H:\Github\angular-pro-sidebar\node_modules\sass-loader\node_modules\schema-utils\dist\validate.js:85:11)
  at Object.loader (H:\Github\angular-pro-sidebar\node_modules\sass-loader\dist\index.js:36:28)

Could you please help me out with this ?

[ALEXOTANO]

Try re-compiling sass files.

npm rebuild node-sass --force

if doesn't work

npm install node-sass`

And try again. =)

[839928622]

thank you so much , It works .

[sameerrede]

C:\work\projects\angular-pro-sidebar-gh-pages>ng serve
Your global Angular CLI version (8.3.24) is greater than your local
version (7.1.2). The local Angular CLI version is used.

To disable this warning use "ng config -g cli.warnings.versionMismatch false".
**Schema validation failed with the following errors:
Data path ".builders['app-shell']" should have required property 'class'.
Error: Schema validation failed with the following errors:
Data path ".builders['app-shell']" should have required property 'class'.
at MergeMapSubscriber.project (C:\work\projects\angular-pro-sidebar-gh-pages\node_modules@angular-devkit\core\src\workspace\workspace.js:215:42)
at MergeMapSubscriber._tryNext (C:\work\projects\angular-pro-sidebar-gh-pages\node_modules\rxjs\internal\operators\mergeMap.js:69:27)
at MergeMapSubscriber._next (C:\work\projects\angular-pro-sidebar-gh-pages\node_modules\rxjs\internal\operators\mergeMap.js:59:18)
at MergeMapSubscriber.Subscriber.next (C:\work\projects\angular-pro-sidebar-gh-pages\node_modules\rxjs\internal\Subscriber.js:67:18)
at MergeMapSubscriber.notifyNext (C:\work\projects\angular-pro-sidebar-gh-pages\node_modules\rxjs\internal\operators\mergeMap.js:92:26)
at InnerSubscriber._next (C:\work\projects\angular-pro-sidebar-gh-pages\node_modules\rxjs\internal\InnerSubscriber.js:28:21)
at InnerSubscriber.Subscriber.next (C:\work\projects\angular-pro-sidebar-gh-pages\node_modules\rxjs\internal\Subscriber.js:67:18)
at MapSubscriber._next (C:\work\projects\angular-pro-sidebar-gh-pages\node_modules\rxjs\internal\operators\map.js:55:26)
at MapSubscriber.Subscriber.next (C:\work\projects\angular-pro-sidebar-gh-pages\node_modules\rxjs\internal\Subscriber.js:67:18)
at SwitchMapSubscriber.notifyNext (C:\work\projects\angular-pro-sidebar-gh-pages\node_modules\rxjs\internal\operators\switchMap.js:86:26)