问如何从获取的二进制数据(二进制数据是从REST接收到的对象的元素之一)以前端角度显示pdf？

EN

**var fs = require('fs');  
var pdfBinary = fs.readFileSync("./TestingPurpose.pdf"); 
var pdf = new mongodb.Binary(pdfBinary);**
db.collection('Test').insert({                    
                 dateTime: new Date(dateTime),
                 studentName: studentName,
                 Principal: principalName,
                 file: pdf }

export class Certificate {
  _id: string;
  dateTime: string;
  studentID: string;
  schoolName: string;
  file: any;
}

import { Certificate } from '../model/certificate.model';
cert: Certificate[];
  // receiving all students info
getCertificates() {
    return this.http.get('http://localhost:5600/aziz/displayAllCertificates');
  }
// to get always get an instant update I use refreshGetCertificates()
  refreshGetCertificates() {
    this.chkSubscrip = this.getCertificates().subscribe((res) => {
      this.cert= res as Certificate[];
    });
  }

export class CertificatesComponent implements OnInit, OnDestroy {
      myPDF: any;
      constructor(
         public userService: UserService,
         private dialog: MatDialog,
  ) { }
ngOnInit() {
    this.userService.refreshGetCertificates();
  }
 pdfView(receiveObj) {

    this.forPDF = !this.forPDF;
    const myUint8 = new Uint8Array(receiveObj);
    this.myPDF= myUint8;
  }
}

<div class="rows">
  <ul class="settings_test headerclass text-center">
    <li style="float: left">ID</li>
    <li>Student-ID</li>
    <li>School</li>
    <li>PDF View</li>
  </ul>
</div>

<div *ngFor="let eachCerts of userService.cert">
  <div class="row">
    <div class="settings_test">
      <li style="width:10%">{{eachCerts._id}}</li>
      <li style="width:10%">{{eachCerts.studentID}}</li>
      <li style="width:10%">{{eachCerts.schoolName}}</li>
      <li style="width:10%"> <button (click) ="pdfView(eachCerts.file)">  View as PDF </button></li>
      <object *ngIf=forPDF data="{{myPDF}}" ></object>
    </div>
  </div>
</div>