Angular でhtml lang を変更する

app.component.ts

import { Component, LOCALE_ID, Injector, Inject } from '@angular/core';
import { DOCUMENT } from '@angular/platform-browser';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss'],
})
export class AppComponent {
  constructor(
    private injector: Injector,
    private titleService: Title,
    @Inject(DOCUMENT) private _document: any
  ) {
    const locale = this.injector.get(LOCALE_ID);
    _document.documentElement.lang = locale;
  }
}