(Node.js) Unzip a ZIP Entry Directly into a BinData Object Using ZipEntry.UnzipToBd

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This example demonstrates how to use the ZipEntry.UnzipToBd method to inflate a ZIP entry directly into a BinData object.

The entry contents are uncompressed entirely in memory without creating a file on disk.

This is useful when:

• Processing ZIP entry data entirely in memory
• Avoiding temporary filesystem files
• Working with binary files such as images, PDFs, or certificates
• Passing uncompressed ZIP data directly to other APIs

The example opens a ZIP archive, locates a PDF entry, inflates it into a BinData object, and then writes the uncompressed bytes to a new file.

Suppose the ZIP archive contains:

docs/report.pdf

The entry is uncompressed directly into memory before optionally being saved to:

qa_output/report.pdf

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;

    var zip = new chilkat.Zip();

    // Open an existing ZIP archive.
    success = zip.OpenZip("qa_data/zips/documents.zip");
    if (success == false) {
        console.log(zip.LastErrorText);
        return;
    }

    // Locate the PDF entry within the ZIP archive.
    var entry = new chilkat.ZipEntry();

    success = zip.EntryOf("docs/report.pdf",entry);
    if (success == false) {
        console.log("ZIP entry not found.");
        zip.CloseZip();
        return;
    }

    // ------------------------------------------------------------
    // Inflate the ZIP entry directly into a BinData object.
    // 
    // The uncompressed bytes are stored entirely in memory.
    // 
    var pdfData = new chilkat.BinData();

    success = entry.UnzipToBd(pdfData);
    if (success == false) {
        console.log(entry.LastErrorText);
        return;
    }

    console.log("Uncompressed size = " + pdfData.NumBytes);
    console.log("");

    // ------------------------------------------------------------
    // Optionally save the uncompressed bytes to a file.
    // 
    success = pdfData.WriteFile("qa_output/report.pdf");
    if (success == false) {
        console.log(pdfData.LastErrorText);
        return;
    }

    zip.CloseZip();

    console.log("PDF extracted successfully.");

}

chilkatExample();