Ruby Requires Chilkat v11.4.0+

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. Ruby

require 'chilkat'

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

js = Chilkat::CkJs.new()

result = Chilkat::CkJsonObject.new()
result.put_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.
    print result.emit() + "\n";

    #  Also examine the LastErrorText.
    print js.lastErrorText() + "\n";
    exit
end

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

funcCall = Chilkat::CkJsonObject.new()
funcCall.put_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.
arg = Chilkat::CkJsonObject.new()
arg.UpdateString("make","Toyota")
arg.UpdateString("model","Corolla")
arg.UpdateInt("year",2022)

#  Create the arguments array.
argsArray = Chilkat::CkJsonArray.new()
argsArray.AddObjectCopyAt(0,arg)

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

print funcCall.emit() + "\n";

success = js.CallFunction(funcCall,result)
if (success == false)
    #  Examine the result for an exception.
    print result.emit() + "\n";

    #  Also examine the LastErrorText.
    print js.lastErrorText() + "\n";
    exit
end

print result.emit() + "\n";

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

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

#  However, the function emitted text to the console.

sbOut = Chilkat::CkStringBuilder.new()
js.ConsoleOutputSb(sbOut)
print sbOut.getAsString() + "\n";

#  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)
print funcCall.emit() + "\n";