C#

Call a JavaScript Function Passing an Object Argument

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Demonstrates how to call a JavaScript function with an argument that is an object. C#

bool success = false;

// This is the JavaScript function we'll call:

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

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

Chilkat.Js js = new Chilkat.Js();

Chilkat.JsonObject 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.
    Debug.WriteLine(result.Emit());

    // Also examine the LastErrorText.
    Debug.WriteLine(js.LastErrorText);
    return;
}

// ------------------------------------------------------------------------------
// Call the function describeCar(car)

Chilkat.JsonObject 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.
Chilkat.JsonObject arg = new Chilkat.JsonObject();
arg.UpdateString("make","Toyota");
arg.UpdateString("model","Corolla");
arg.UpdateInt("year",2022);

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

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

Debug.WriteLine(funcCall.Emit());

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

    // Also examine the LastErrorText.
    Debug.WriteLine(js.LastErrorText);
    return;
}

Debug.WriteLine(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.

Chilkat.StringBuilder sbOut = new Chilkat.StringBuilder();
js.ConsoleOutputSb(sbOut);
Debug.WriteLine(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);
Debug.WriteLine(funcCall.Emit());