(JavaScript) 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

Note

This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.

var success = false;

var zip = new CkZip();

// 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 CkZipEntry();

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 CkBinData();

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.");