test.ts

import { Component, OnInit } from '@angular/core';
import { HttpClient } from '@angular/common/http';

declare const loadDocument: any;

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})

export class AppComponent implements OnInit {
  title = 'my-editor-app';
  webSocketUrl = 'wss://backend.textcontrol.com?access-token=123';

  private URL = '../assets/docs/test.tx';

  constructor(private httpClient: HttpClient) {}

  ngOnInit() {
    this.httpClient.get(this.URL, {responseType:'blob'}).subscribe((response) => {
      loadDocument(response);
    });
  }

}