How to add custom metadata in existing PDF file in react js application?

[shitrerohit]

I have created the one react js application and installed the pdf-lib library and tried to add custom metadata.
Code-base: React js application
PDF-LIB version: 1.9.1

I am trying to add custom metadata in an existing PDF file using below link code reference.
#55 (comment)
Facing some issues related to importing the variables from package that are below,

1. Property 'PDFDictionary' does not exist on type 'PDFDocument'.
2. Cannot find name 'PDFDocumentWriter'.

We expect correct way to add the custom metadata in existing PDF file.