How to setup SASS/SCSS/sass-loader in Nuxt

Question

I have a Nuxt app and I want to use the CSS pre-processor.
I installed the sass-loader fibers dependencies, but after installation, a message appears in the application console, which I presented in the image and in the code

This is code err:

 WARN  [email protected] is installed but ^4.46.0 is expected                                                                                                                                                                     17:22:44


 WARN  [email protected] is installed but ^10.1.1 is expected

     


Rule can only have one resource source (provided resource and test + include + exclude) in {                                                                                                                           17:22:46
  "use": [
    {
      "loader": "/home/sergey/all_project/pro_projects_all_language/empty/node_modules/babel-loader/lib/index.js",
      "options": {
        "configFile": false,
        "babelrc": false,
        "cacheDirectory": true,
        "envName": "server",
        "presets": [
          [
            "/home/sergey/all_project/pro_projects_all_language/empty/node_modules/@nuxt/babel-preset-app/src/index.js",
            {
              "corejs": {
                "version": 3
              }
            }
          ]
        ]
      },
      "ident": "clonedRuleSet-29[0].rules[0].use[0]"
    }
  ]
}

  "use": [
  {
  "loader": "node_modules/babel-loader/lib/index.js",
  "options": {
  "configFile": false,
  "babelrc": false,
  "cacheDirectory": true,
  "envName": "server",
  "presets": [
  [
  "node_modules/@nuxt/babel-preset-app/src/index.js",
  {
  "corejs": {
  "version": 3
  }
  }
  ]
  ]
  },
  "ident": "clonedRuleSet-29[0].rules[0].use[0]"
  }
  ]
  }
  at checkResourceSource (node_modules/@nuxt/webpack/node_modules/webpack/lib/RuleSet.js:167:11)
  at Function.normalizeRule (node_modules/@nuxt/webpack/node_modules/webpack/lib/RuleSet.js:198:4)
  at node_modules/@nuxt/webpack/node_modules/webpack/lib/RuleSet.js:110:20
  at Array.map (<anonymous>)
  at Function.normalizeRules (node_modules/@nuxt/webpack/node_modules/webpack/lib/RuleSet.js:109:17)
  at new RuleSet (node_modules/@nuxt/webpack/node_modules/webpack/lib/RuleSet.js:104:24)
  at new NormalModuleFactory (node_modules/@nuxt/webpack/node_modules/webpack/lib/NormalModuleFactory.js:115:18)
  at Compiler.createNormalModuleFactory (node_modules/@nuxt/webpack/node_modules/webpack/lib/Compiler.js:636:31)
  at Compiler.newCompilationParams (node_modules/@nuxt/webpack/node_modules/webpack/lib/Compiler.js:653:30)
  at Compiler.compile (node_modules/@nuxt/webpack/node_modules/webpack/lib/Compiler.js:661:23)
  at node_modules/@nuxt/webpack/node_modules/webpack/lib/Watching.js:77:18
  at AsyncSeriesHook.eval [as callAsync] (eval at create (node_modules/tapable/lib/HookCodeFactory.js:33:10), <anonymous>:24:1)
  at AsyncSeriesHook.lazyCompileHook (node_modules/tapable/lib/Hook.js:154:20)
  at Watching._go (node_modules/@nuxt/webpack/node_modules/webpack/lib/Watching.js:41:32)
  at node_modules/@nuxt/webpack/node_modules/webpack/lib/Watching.js:33:9
  at Compiler.readRecords (node_modules/@nuxt/webpack/node_modules/webpack/lib/Compiler.js:529:11)

I tried reinstalling dependencies, reinstalling a completely clean Nuxt application, and still the problem remains.

Answer 1

To install SASS in Nuxt, you have to run yarn add -D sass [email protected] (or npm i -D [email protected] --save-exact && npm i -D sass).

The version of sass-loader needs to be exact and set at the latest 10.x.x because the next one (11.0.0) is using Webpack5, hence being a breaking change because Nuxt2 is only running on Webpack4 as shown here: https://github.com/webpack-contrib/sass-loader/releases

IF then, you still cannot use <style lang="sass"> in your .vue components, then proceed.

---

Add this to your nuxt.config.js file

export default {
  build: {
    loaders: {
      sass: {
        implementation: require('sass'),
      },
      scss: {
        implementation: require('sass'),
      },
    },
  }
}

Here is a working repo with the latest recommended sass (dart-sass) setup working properly with this kind of code

<template>
  <div>
    <span class="test">
      Hello there
    </span>
  </div>
</template>

<style lang="sass" scoped>
div
  .test
    color: red
</style>

PS: if SASS is properly installed, then SCSS is working as good because it's basically the same thing.

---

If you have some warning on some things being deprecated like / for divison or any listed here: https://sass-lang.com/documentation/breaking-changes
You can refer to this answer for a fix: https://stackoverflow.com/a/68648204/8816585

Answer 2

kissu's answer worked for me, but not right away. Finally I managed to fix the problem by downgrading the loader also followed by removing and installing again nuxt.