pdf viewer ionic 4

1ionic cordova plugin add cordova-plugin-document-viewer
2npm install @ionic-native/document-viewer
3
4import { DocumentViewer } from '@ionic-native/document-viewer/ngx';
5constructor(private document: DocumentViewer) { }
6const options: DocumentViewerOptions = {
7  title: 'My PDF'
8}
9this.document.viewDocument('assets/myFile.pdf', 'application/pdf', options)