(Go) Call a JavaScript Function Passing an Object Argument

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Note: This example requires Chilkat v11.4.0 or greater.

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    success := false

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

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

    sbScript := StringBuilder_Ref.html">chilkat.NewStringBuilder()
    sbScript.Append("function describeCar(car) { console.log(`This is a ${car.year} ${car.make} ${car.model}.`); }")

    js := Js_Ref.html">chilkat.NewJs()

    result := JsonObject_Ref.html">chilkat.NewJsonObject()
    result.SetEmitCompact(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.
        fmt.Println(*result.Emit())

        // Also examine the LastErrorText.
        fmt.Println(js.LastErrorText())
        sbScript.DisposeStringBuilder()
        js.DisposeJs()
        result.DisposeJsonObject()
        return
    }

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

    funcCall := JsonObject_Ref.html">chilkat.NewJsonObject()
    funcCall.SetEmitCompact(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.
    arg := JsonObject_Ref.html">chilkat.NewJsonObject()
    arg.UpdateString("make","Toyota")
    arg.UpdateString("model","Corolla")
    arg.UpdateInt("year",2022)

    // Create the arguments array.
    argsArray := JsonArray_Ref.html">chilkat.NewJsonArray()
    argsArray.AddObjectCopyAt(0,arg)

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

    fmt.Println(*funcCall.Emit())

    success = js.CallFunction(funcCall,result)
    if success == false {
        // Examine the result for an exception.
        fmt.Println(*result.Emit())

        // Also examine the LastErrorText.
        fmt.Println(js.LastErrorText())
        sbScript.DisposeStringBuilder()
        js.DisposeJs()
        result.DisposeJsonObject()
        funcCall.DisposeJsonObject()
        arg.DisposeJsonObject()
        argsArray.DisposeJsonArray()
        return
    }

    fmt.Println(*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.

    sbOut := StringBuilder_Ref.html">chilkat.NewStringBuilder()
    js.ConsoleOutputSb(sbOut)
    fmt.Println(*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)
    fmt.Println(*funcCall.Emit())

    sbScript.DisposeStringBuilder()
    js.DisposeJs()
    result.DisposeJsonObject()
    funcCall.DisposeJsonObject()
    arg.DisposeJsonObject()
    argsArray.DisposeJsonArray()
    sbOut.DisposeStringBuilder()