encrypt and decrypt zip file

[sharmapn]

I am able to encrypt and decrypt the contents of a text file using the browserPGP tool.
This is my encryption code. I am not including the input of key from a textbox.

const publicKeys = await Promise.all(publicKeysArmored.map(armoredKey => openpgp.readKey({ armoredKey }))); 
var blob = new Blob(["Lorem Ipsum is simply dummy text of the printing and typesetting industry. "], { type: "text/plain;charset=utf-8" });
//saveAs(blob,'decrypted.txt');
 
  var file = new File([blob], "plaintext.txt", { type: "text/plain", });
  var fileReader = new FileReader();
  
  fileReader.onload = function() 
  {
        const message = await openpgp.createMessage({ text: fileReader.result}); 
        const encrypted = await openpgp.encrypt(
        {        
           message, 
           encryptionKeys: publicKeys
        });        
         var blob3 = new Blob([encrypted],{type: 'text/plain'} );    
         saveAs(blob3, 'encrypted.txt'); 
  }
  fileReader.readAsText(file);
}

However, I am not able to encrypt and decrypt a zip file. The decrypted zip file is always corrupt.
I use the same code, but convert the zip file contents into plaintext, which I think is not a good idea.

var zipFile = new JSZip();
zipFile.file("Metadata.txt", 'Lorem Ipsum is simply dummy text of the printing and typesetting industry. ');

var plaintextbytes = new Uint8Array(zipFile);
var plainTextString = new TextDecoder().decode(plaintextbytes);
const message = await openpgp.createMessage({ text: plainTextString });