(Node.js) Call a JavaScript Function Passing an Object Argument

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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 describeCar(car) {
    // 	console.log(`This is a ${car.year} ${car.make} ${car.model}.`);
    // }

    var sbScript = new chilkat.StringBuilder();
    sbScript.Append("function describeCar(car) { console.log(`This is a ${car.year} ${car.make} ${car.model}.`); }");

    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 describeCar(car)

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

    // Create JSON specifying the function name and arguments
    // In this case, there is only 1 argument, and it is an object.

    // {
    //   "name": "describeCar",
    //   "args": [
    //     {
    //       "make": "Toyota",
    //       "model": "Corolla",
    //       "year": 2022
    //     }
    //   ]
    // }

    funcCall.UpdateString("name","describeCar");

    // Create the JSON object that is the argument.
    var arg = new chilkat.JsonObject();
    arg.UpdateString("make","Toyota");
    arg.UpdateString("model","Corolla");
    arg.UpdateInt("year",2022);

    // Create the arguments array.
    var argsArray = new chilkat.JsonArray();
    argsArray.AddObjectCopyAt(0,arg);

    // Add the "args" array to the funcCall.
    funcCall.AppendArrayCopy("args",argsArray);

    console.log(funcCall.Emit());

    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());

    // The describeCar JavaScript function returns nothing. 
    // Therefore, the result is "undefined".

    // {
    //   "type": "undefined",
    //   "value": "undefined"
    // }

    // However, the function emitted text to the console.

    var sbOut = new chilkat.StringBuilder();
    js.ConsoleOutputSb(sbOut);
    console.log(sbOut.GetAsString());

    // Output:
    // This is a 2022 Toyota Corolla.

    // -----------------------------------------------------------
    // Note: If the object argument is simple, this is an alternative
    // and simpler way of creating the funcCall:

    funcCall.Clear();
    funcCall.UpdateString("name","describeCar");
    funcCall.UpdateString("args[0].make","Toyota");
    funcCall.UpdateString("args[0].model","Corolla");
    funcCall.UpdateInt("args[0].year",2022);
    console.log(funcCall.Emit());

}

chilkatExample();