(JavaScript) Set a Custom Last-Modified Date in a Gzip File

See more Gzip Examples

This example demonstrates how to use the SetDt method to specify a custom last-modified date and time that will be embedded in a Gzip file.

A CkDateTime object is first initialized with a specific date/time using an RFC 822 formatted string. This date/time is then applied to the Gzip object using SetDt.

When a compression method is called (such as CompressStringToFile), the specified date/time is included in the Gzip metadata. This allows the resulting .gz file to carry a meaningful timestamp rather than using the current system time.

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;

// This example demonstrates how to set a custom last-modified date/time
// that will be embedded in a Gzip file.

var gzip = new CkGzip();
var dt = new CkDateTime();

// Set the date/time using a timestamp format (ISO 8601 style):
dt.SetFromTimestamp("2025-11-15T12:45:26-05:00");

// Apply the date/time to the Gzip object:
success = gzip.SetDt(dt);
if (success == false) {
    console.log(gzip.LastErrorText);
    return;
}

// Compress a string so the custom date/time is embedded in the .gz:
var inputStr = "Example text for Gzip compression.";
success = gzip.CompressStringToFile(inputStr,"utf-8","output.gz");
if (success == false) {
    console.log(gzip.LastErrorText);
    return;
}

console.log("Gzip file created with custom last-modified date.");