cant use laravel mix

i do npm install and after that run npm dev

and i get that error ( itry to delete and install again and i get the same error)

WARNING in ./resources/assets/js/bootstrap.js Module not found: Error: Can't resolve 'bootstrap-sass' in '\resources\assets\js' @ ./resources/assets/js/bootstrap.js 13:2-27 @ ./resources/assets/js/app.js @ multi ./resources/assets/js/app.js ./resources/assets/sass/app.scss

ERROR in ./node_modules/css-loader??ref--8-2!./node_modules/postcss-loader/lib??postcss!./node_modules/resolve-url-loader??ref--8-4!./node_modules/sass-loader/lib/loader.js??ref--8-5!./resources/assets/sass/app.scss Module build failed: undefined ^ File to import not found or unreadable: node_modules/bootstrap-sass/assets/stylesheets/bootstrap. Parent style sheet: stdin in \resources\assets\sass\app.scss (line 9, column 1) @ ./resources/assets/sass/app.scss 4:14-266 @ multi ./resources/assets/js/app.js ./resources/assets/sass/app.scss

ERROR in ./resources/assets/sass/app.scss Module build failed: ModuleBuildError: Module build failed: undefined ^ File to import not found or unreadable: node_modules/bootstrap-sass/assets/stylesheets/bootstrap. Parent style sheet: stdin in \resources\assets\sass\app.scss (line 9, column 1) at runLoaders (node_modules\webpack\lib\NormalModule.js:195:19) at node_modules\loader-runner\lib\LoaderRunner.js:364:11 at \node_modules\loader-runner\lib\LoaderRunner.js:230:18 at context.callback (node_modules\loader-runner\lib\LoaderRunner.js:111:13) at Object.asyncSassJobQueue.push [as callback] (\node_modules\sass-loader\lib\loader.js:55:13) at Object. (node_modules\async\dist\async.js:958:16) at options.error (node_modules\node-sass\lib\index.js:294:32) @ ./resources/assets/sass/app.scss @ multi ./resources/assets/js/app.js ./resources/assets/sass/app.scss