Error when compiling Universal Angular with ngx-translate
问题 I am configuring ngx-translate as follows: translate-server-loader.service.ts import {Observable} from "rxjs/Observable"; import {TranslateLoader} from '@ngx-translate/core'; import { Injectable } from '@angular/core'; import {makeStateKey, StateKey, TransferState} from '@angular/platform-browser'; import {TranslateHttpLoader} from '@ngx-translate/http-loader'; import {HttpClient} from '@angular/common/http'; @Injectable() export class TranslateBrowserLoader implements TranslateLoader {