Ruby

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. 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";