(Node.js) Transition from BeginCompressStringENC to FirstChunk/LastChunk

Provides instructions for replacing deprecated BeginCompressStringENC method calls with using FirstChunk/LastChunk properties.

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;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    var sbCompressedBase64 = new chilkat.StringBuilder();

    var compress = new chilkat.Compression();
    compress.Algorithm = "deflate";
    compress.Charset = "utf-8";
    compress.EncodingMode = "base64";

    var sbIndex = new chilkat.StringBuilder();

    // ----------------------------------------------------------------------------------
    // This is the deprecated way of compressing in chunks using Begin/More/End methods..
    // ----------------------------------------------------------------------------------
    var i;
    for (i = 0; i <= 24; i++) {
        // Note: It is possible (and normal) for a BeginCompress* or MoreCompress* method to return
        // an empty string (or 0 bytes).  When this happens, the input data is not lost.  It will be flushed
        // in a subsequent call.
        sbIndex.Clear();
        sbIndex.AppendInt(i);
        if (i == 0) {
            sbCompressedBase64.Append(compress.BeginCompressStringENC(sbIndex.GetAsString()));
        }
        else {
            sbCompressedBase64.Append(compress.MoreCompressStringENC(sbIndex.GetAsString()));
        }

        sbCompressedBase64.Append(compress.MoreCompressStringENC(": This is a line of data to be compressed...\r\n"));
    }

    // Flush any remaining output.
    sbCompressedBase64.Append(compress.EndCompressStringENC());

    console.log("The base64 encoded compressed text:");
    console.log(sbCompressedBase64.GetAsString());

    // Decompress in one call:
    var originalText = compress.DecompressStringENC(sbCompressedBase64.GetAsString());
    console.log(originalText);

    // ----------------------------------------------------------------------------------
    // This is new way of compressing in chunks using FirstChunk and LastChunk properties
    // ----------------------------------------------------------------------------------

    sbCompressedBase64.Clear();

    compress.FirstChunk = true;
    compress.LastChunk = false;

    var bdCompressed = new chilkat.BinData();
    var sbUncompressedChunk = new chilkat.StringBuilder();

    for (i = 0; i <= 24; i++) {
        if (i == 24) {
            compress.LastChunk = true;
        }

        sbUncompressedChunk.Clear();
        sbUncompressedChunk.AppendInt(i);
        sbUncompressedChunk.Append(": This is a line of data to be compressed...\r\n");

        compress.CompressSb(sbUncompressedChunk,bdCompressed);

        compress.FirstChunk = false;
    }

    console.log("The base64 encoded compressed text:");
    console.log(bdCompressed.GetEncoded("base64"));

    // Decompress in one call:
    originalText = compress.DecompressStringENC(bdCompressed.GetEncoded("base64"));
    console.log(originalText);

}

chilkatExample();