Xojo Plugin Requires Chilkat v11.4.0+

Call a JavaScript Function Passing an Object Argument

See more JavaScript Examples

Demonstrates how to call a JavaScript function with an argument that is an object. Xojo Plugin

Dim success As Boolean
success = False

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

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

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

Dim js As New Chilkat.Js

Dim result As 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) Then
    //  Examine the result for an exception.
    System.DebugLog(result.Emit())

    //  Also examine the LastErrorText.
    System.DebugLog(js.LastErrorText)
    Return
End If

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

Dim funcCall As 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
//      }
//    ]
//  }

success = funcCall.UpdateString("name","describeCar")

//  Create the JSON object that is the argument.
Dim arg As New Chilkat.JsonObject
success = arg.UpdateString("make","Toyota")
success = arg.UpdateString("model","Corolla")
success = arg.UpdateInt("year",2022)

//  Create the arguments array.
Dim argsArray As New Chilkat.JsonArray
success = argsArray.AddObjectCopyAt(0,arg)

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

System.DebugLog(funcCall.Emit())

success = js.CallFunction(funcCall,result)
If (success = False) Then
    //  Examine the result for an exception.
    System.DebugLog(result.Emit())

    //  Also examine the LastErrorText.
    System.DebugLog(js.LastErrorText)
    Return
End If

System.DebugLog(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.

Dim sbOut As New Chilkat.StringBuilder
js.ConsoleOutputSb sbOut
System.DebugLog(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 
success = funcCall.UpdateString("name","describeCar")
success = funcCall.UpdateString("args[0].make","Toyota")
success = funcCall.UpdateString("args[0].model","Corolla")
success = funcCall.UpdateInt("args[0].year",2022)
System.DebugLog(funcCall.Emit())