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JavaScript

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 is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.
JavaScript
var success = false;

success = false;

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

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

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

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 CkZipEntry();

// 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.");