(Node.js) Call a JavaScript Function Returning a String

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Demonstrates how to call a JavaScript function that returns a string.

Note: This example requires Chilkat v11.4.0 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 is the JavaScript function we'll call:

    // function greet(name) {
    //     return "Hello, " + name + "!";
    // }

    var sbScript = new chilkat.StringBuilder();
    sbScript.Append("function greet(name) { return \"Hello, \" + name + \"!\"; }");

    var js = new chilkat.Js();

    var result = new chilkat.JsonObject();
    result.EmitCompact = false;

    // Call Eval to add the function to the context's global object
    success = js.Eval(sbScript,result);
    if (success == false) {
        // Examine the result for an exception.
        console.log(result.Emit());

        // Also examine the LastErrorText.
        console.log(js.LastErrorText);
        return;
    }

    // ------------------------------------------------------------------------------
    // Call the function greet("Michael")

    var funcCall = new chilkat.JsonObject();

    // Create JSON specifying the function name and arguments

    // {
    //   "name": "greet",
    //   "args": [ "Michael" ]
    // }

    funcCall.UpdateString("name","greet");
    funcCall.UpdateString("args[0]","Michael");

    success = js.CallFunction(funcCall,result);
    if (success == false) {
        // Examine the result for an exception.
        console.log(result.Emit());

        // Also examine the LastErrorText.
        console.log(js.LastErrorText);
        return;
    }

    console.log(result.Emit());

    // Output:
    // {
    //   "type": "string",
    //   "value": "Hello, Michael!"
    // }

    var retval = result.StringOf("value");
    console.log(retval);

    // Output:
    // Hello, Michael!

}

chilkatExample();