(Node.js) Find a ZIP Entry by EntryID Using EntryById

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This example demonstrates how to use the EntryById method to retrieve a ZIP entry using its unique EntryID.

Each ZipEntry object has an EntryID property that uniquely identifies the entry within the currently open ZIP object.

This is useful when:

• An application stores EntryID values for later use
• ZIP entries need to be retrieved without searching by filename
• Multiple entries may have similar names or paths

The example:

• Opens a ZIP archive
• Retrieves an entry using EntryAt
• Saves the entry's EntryID
• Uses EntryById to retrieve the same entry later

Note: This example requires Chilkat v11.0.0 or greater.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOS

var os = require('os');
if (os.platform() == 'win32') {  
  var chilkat = require('@chilkat/ck-node23-win64'); 
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node23-linux-arm');
    } else if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node23-linux-arm64');
    } else {
        var chilkat = require('@chilkat/ck-node23-linux-x64');
    }
} else if (os.platform() == 'darwin') {
  var chilkat = require('@chilkat/ck-node23-mac-universal');
}

function chilkatExample() {

    var success = false;

    success = false;

    // Open an existing ZIP archive.
    var zip = new chilkat.Zip();

    success = zip.OpenZip("example.zip");
    if (success == false) {
        console.log(zip.LastErrorText);
        return;
    }

    // Retrieve the first entry in the ZIP archive.
    var entry = new chilkat.ZipEntry();

    success = zip.EntryAt(0,entry);
    if (success == false) {
        console.log(zip.LastErrorText);
        return;
    }

    console.log("Original entry:");
    console.log("  FileName: " + entry.FileName);
    console.log("  EntryID: " + entry.EntryID);
    console.log("");

    // Save the EntryID for later use.
    var entryId = entry.EntryID;

    // Create another ZipEntry object.
    var entry2 = new chilkat.ZipEntry();

    // Retrieve the same entry using EntryById.
    success = zip.EntryById(entryId,entry2);
    if (success == false) {
        console.log(zip.LastErrorText);
        return;
    }

    console.log("Entry retrieved by EntryID:");
    console.log("  FileName: " + entry2.FileName);
    console.log("  EntryID: " + entry2.EntryID);
    console.log("");

    // The filenames and EntryID values should match.
    zip.CloseZip();

    console.log("Done.");

}

chilkatExample();