Module build failed: TypeError: Cannot read property 'sassLoader' of undefined

Question

i have updated Angular5 to Angular 6. Until now, i have been using webpack-dev-server to start the app. I wanted to get the ng serve to serve the application. However, i am getting this error below when i run ng serve:- Module build failed: TypeError: Cannot read property 'sassLoader' of undefined at getLoaderConfig (C:\Work\Dev\Accesslint-Checkins\Accesslint-UI\node_modules\sass-loader\index.js:389:39) at Object.module.exports (C:\Work\Dev\Accesslint-Checkins\Accesslint-UI\node_modules\sass-loader\index.js:42:23) ERROR in ./src/assets/sass/app.scss (./node_modules/raw-loader!./node_modules/postcss-loader/lib??embedded!./node_modules/sass-loader??ref--15-3!./src/assets/sass/app.scss)

Following is the angular.json and somehow there is no angular-cli.json :-

{
  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "Accesslint-ui": {
      "root": "",
      "sourceRoot": "src",
      "projectType": "application",
      "prefix": "app",
      "schematics": {},
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-angular:browser",
          "options": {
            "outputPath": "dist/Accesslint-ui",
            "index": "src/index.html",
            "main": "src/main.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "src/tsconfig.app.json",
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ],
            "styles": [
			"node_modules/bootstrap/scss/bootstrap.scss",
              "src/styles.scss",   
			  "src/assets/sass/app.scss"
            ],
            "scripts": []
          },
          "configurations": {
            "production": {
              "fileReplacements": [
                {
                  "replace": "src/environments/environment.ts",
                  "with": "src/environments/environment.prod.ts"
                }
              ],
              "optimization": true,
              "outputHashing": "all",
              "sourceMap": false,
              "extractCss": true,
              "namedChunks": false,
              "aot": true,
              "extractLicenses": true,
              "vendorChunk": false,
              "buildOptimizer": true
            }
          }
        },
        "serve": {
          "builder": "@angular-devkit/build-angular:dev-server",
          "options": {
            "browserTarget": "Accesslint-ui:build"
          },
          "configurations": {
            "production": {
              "browserTarget": "Accesslint-ui:build:production"
            }
          }
        },
        "extract-i18n": {
          "builder": "@angular-devkit/build-angular:extract-i18n",
          "options": {
            "browserTarget": "Accesslint-ui:build"
          }
        },
        "test": {
          "builder": "@angular-devkit/build-angular:karma",
          "options": {
            "main": "src/test.ts",
            "polyfills": "src/polyfills.ts",
            "tsConfig": "src/tsconfig.spec.json",
            "karmaConfig": "src/karma.conf.js",
            "styles": [
              "src/styles.css"
            ],
            "scripts": [],
            "assets": [
              "src/favicon.ico",
              "src/assets"
            ]
          }
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": [
              "src/tsconfig.app.json",
              "src/tsconfig.spec.json"
            ],
            "exclude": [
              "**/node_modules/**"
            ]
          }
        }
      }
    },
    "Accesslint-ui-e2e": {
      "root": "e2e/",
      "projectType": "application",
      "architect": {
        "e2e": {
          "builder": "@angular-devkit/build-angular:protractor",
          "options": {
            "protractorConfig": "e2e/protractor.conf.js",
            "devServerTarget": "Accesslint-ui:serve"
          },
          "configurations": {
            "production": {
              "devServerTarget": "Accesslint-ui:serve:production"
            }
          }
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": "e2e/tsconfig.e2e.json",
            "exclude": [
              "**/node_modules/**"
            ]
          }
        }
      }
    }
  },
  "defaultProject": "Accesslint-ui"
}

clear npm cache using "npm cache clean --force" and again run npm i — Aniket Avhad

Suresh Kumar Ariya Suresh Kumar Ariya · Accepted Answer · 2018-08-27T12:42:16

Also please check what is the node-sass & sass-loader version you are using in your application. Try to use the latest version which will solve this issue.

Here is the version using in my application

node-sass : 4.9.3
sass-loader: 7.1.0

Module build failed: TypeError: Cannot read property 'sassLoader' of undefined

1 Answers