import { PSPDFKit } from '@awesome-cordova-plugins/pspdfkit-cordova/ngx';
constructor(private pspdfkit: PSPDFKit) { }
...
this.pspdfkit.setLicenseKey("YOUR KEY");
this.pspdfkit.present('document.pdf', {pageMode: 'single', backgroundColor: "black"})
  .then(result => {
     console.log(result); 
  })
  .catch(error => {
     console.log(error); 
  });
}
this.pspdfkit.setPage(1, true);