[Webpack] PostCSS received undefined instead of CSS string

sass-loader 추가 후 빌드 에러 발생

{
    test:/\.(css|scss|sass)$/i,
    use: [
        !devMode
        ? MiniCssExtractPlugin.loader
        : 'style-loader', 
        'css-loader',
        'sass-loader'
    ]
},

 

sass 추가 설치 후 해결

yarn add sass -d

 

참조: https://velog.io/@devstefancho/webpack-sass-loader-Error-Cannot-find-module-sass

[webpack] sass-loader Error (Cannot find module 'sass')