如何在ionic V4中读取本地JSON文件？

npm install @angular/common@latest @angular/compiler@latest @angular/compiler-cli@latest @angular/core@latest @angular/forms@latest @angular/http@latest @angular/platform-browser@latest @angular/platform-browser-dynamic@latest @angular/platform-server@latest @angular/router@latest @angular/service-worker@latest @angular/animations@latest --save

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Injectable({
  providedIn: 'root'
})
export class DataService {

  constructor(private http: HttpClient) { }

  getData() {
    return this.http.get('assets/data.json');
  }
}

import { Component } from '@angular/core';
import { DataService } from '../data.service';

@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
})
export class HomePage {

  jsonData: any;

  constructor(private dataService: DataService) {}

  ngOnInit() {
    this.dataService.getData().subscribe(data => {
      this.jsonData = data;
      console.log(this.jsonData);
    });
  }
}