Answers for "Module '"@angular/common/http"' has no exported member 'RequestOptions'"

Module '"@angular/common/http"' has no exported member 'RequestOptions'

//RequestOptions is deprecated if you use @angular/common/http
//try this solution instead:
import { HttpHeaders } from '@angular/common/http';
...
const httpOptions = {
        headers: new HttpHeaders({
          'Content-Type':  'application/json',
          'Authorization': environment.key
          })
        };
...