Sass Loader Error: Invalid options object that does not match the API schema

Question

I'm using VueJS with the framework VuetifyJS (v2.0.19). I'm getting this error after running npm run serve:

Sass Loader has been initialised using an options object that does not match the API schema.

What I tried: I've deleted the node_modules folder and reinstalled/updated all npm packages and node.js to the latest stable version.

Full error message:

 error  in ./node_modules/vuetify/src/components/VRangeSlider/VRangeSlider.sass

Module build failed (from ./node_modules/sass-loader/dist/cjs.js):
ValidationError: Invalid options object. Sass Loader has been initialised using an options object that does not match the API schema.
 - options has an unknown property 'indentedSyntax'. These properties are valid:
   object { implementation?, sassOptions?, prependData?, sourceMap?, webpackImporter? }
    at validate (/home/do/Desktop/A/Projects/Ral/AppCLI3/node_modules/sass-loader/node_modules/schema-utils/dist/validate.js:50:11)
    at Object.loader (/home/do/Desktop/A/Projects/Ral/AppCLI3/node_modules/sass-loader/dist/index.js:36:28)

 @ ./node_modules/vuetify/src/components/VRangeSlider/VRangeSlider.sass 4:14-208 14:3-18:5 15:22-216
 @ ./node_modules/vuetify/lib/components/VRangeSlider/VRangeSlider.js
 @ ./node_modules/vuetify/lib/components/VRangeSlider/index.js
 @ ./node_modules/vuetify/lib/components/index.js
 @ ./node_modules/vuetify/lib/index.js
 @ ./src/main.js
 @ multi (webpack)-dev-server/client?http://192.168.2.115:8080/sockjs-node (webpack)/hot/dev-server.js ./src/main.js

 error  in ./node_modules/vuetify/src/styles/main.sass

My package.json:

  {
  "name": "app",
  "version": "0.1.0",
  "private": false,
  "scripts": {
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build",
    "lint": "vue-cli-service lint"
  },
  "dependencies": {
    "core-js": "^3.2.1",
    "fibers": "^4.0.1",
    "firebase": "^7.0.0",
    "material-icons": "^0.3.1",
    "register-service-worker": "^1.6.2",
    "vue": "^2.6.10",
    "vue-flickity": "^1.2.1",
    "vue-router": "^3.1.3",
    "vuetify": "^2.0.19",
    "vuex": "^3.1.1"
  },
  "devDependencies": {
    "@mdi/font": "^4.4.95",
    "@vue/cli-plugin-babel": "^3.11.0",
    "@vue/cli-plugin-eslint": "^3.11.0",
    "@vue/cli-plugin-pwa": "^3.11.0",
    "@vue/cli-service": "^3.11.0",
    "@vue/eslint-config-prettier": "^5.0.0",
    "babel-eslint": "^10.0.3",
    "eslint": "^6.5.1",
    "eslint-plugin-prettier": "^3.1.1",
    "eslint-plugin-vue": "^5.2.3",
    "material-design-icons-iconfont": "^5.0.1",
    "node-sass": "^4.12.0",
    "prettier": "1.18.2",
    "sass-loader": "^8.0.0",
    "stylus": "^0.54.7",
    "stylus-loader": "^3.0.2",
    "uglifyjs-webpack-plugin": "^2.2.0",
    "vue-cli-plugin-vuetify": "^0.6.3",
    "vue-loader": "^15.7.1",
    "vue-template-compiler": "^2.6.10",
    "vuetify-loader": "^1.3.0",
    "webpack": "^4.41.0",
    "webpack-cli": "^3.3.9"
  },
  "eslintConfig": {
    "root": true,
    "env": {
      "node": true
    },
    "extends": [
      "plugin:vue/essential",
      "@vue/prettier"
    ],
    "rules": {
      "no-console": "off"
    },
    "parserOptions": {
      "parser": "babel-eslint"
    }
  },
  "postcss": {
    "plugins": {
      "autoprefixer": {}
    }
  },
  "browserslist": [
    "> 1%",
    "last 2 versions"
  ]
}

How to fix this issue?

Answer 1

Seems same issue like here: https://github.com/JeffreyWay/laravel-mix/issues/2206

Solution is

npm uninstall --save-dev sass-loader
npm install --save-dev [email protected]

Answer 2

Problem

Based on vue-cli - github issue, If you did upgrade your sass-loader from v7 to 8 or 9, You may have faced with the validation-error for invalid options :

vue.config.js(valid syntax for sass-loaderv7 in webpack)

  css: {
    loaderOptions: {
      sass: {
        data: `@import "@/assets/styles/variables/index.scss";`
      }
    }
  }

errors

object:
    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 'data'. These properties are valid:

sass-loader v8.0 Breaking Changes

You should know that v8. has below breaking changes

• minimum required webpack version is 4.36.0
• minimum required node.js version is 8.9.0
• move all sass (includePaths, importer, functions) options to the sassOptions option. The functions option can't be used as Function, you should use sassOption as Function to achieve this.
• the data option was renamed to the prependData option default value of the sourceMap option depends on the devtool value (eval/false values don't enable source map generation)

Solution v8

As the docs says:

• move all sass (includePaths, importer, functions) options to the sassOptions option. The functions option can't be used as Function, you should use sassOption as Function to achieve this.
• the data option was renamed to the prependData option

sass-loader v9.0 Breaking Changes

You should know that v9. has below breaking changes

• BREAKING CHANGES minimum supported Nodejs version is 10.13
• prefer sass (dart-sass) by default, it is strongly recommended to migrate on sass (dart-sass)
• the prependData option was removed in favor the additionalData option, see docs
• when the sourceMap is true, sassOptions.sourceMap, sassOptions.sourceMapContents, sassOptions.sourceMapEmbed, sassOptions.sourceMapRoot and sassOptions.omitSourceMapUrl will be ignored.

Solution v9

In ver9 as you can see in the options, sassOption , additionalData, if we change data to additionalData it will fix the invalid options errors.

  css: {
    loaderOptions: {
      sass: {
        additionalData: `@import "@/assets/styles/variables/index.scss";`
      }
    }
  }