tsconfig.json的 "baseUrl": "./",同一级加配置ts别名路径

...
    // 全局ts路径别名
    "paths": {
      "@app/*": ["src/app/*"],
      "@assets/*": ["src/assets/*"],
      "@env/*": ["src/environments/*"],
    },
...

angular.json>projects>...>architect>build>options>加入配置css别名路径

...
            "stylePreprocessorOptions": {
              "includePaths": ["src/assets/css"]
            },
...

引用的代码

引用ts

import { SgService } from '@app/common/sg.service';

引用scss

@import 'sg';

@import 'sg1';