Measuring the area of an artwork

I tried this script below but it wouldn't work:

// Adobe Illustrator script to calculate total area of a fill color in a PDF file

// Function to calculate the area of a path item
function calculateArea(pathItem) {
var area = 0;

// Check if the pathItem has a fill color
if (pathItem.filled) {
// Get the color of the fill
var fillColor = pathItem.fillColor;

// Check if the fill color is a solid color
if (fillColor instanceof RGBColor) {
// Calculate the area of the pathItem
area += pathItem.area;
}
}

return area;
}

// Main function to calculate total area
function calculateTotalArea() {
var doc = app.activeDocument;
var totalArea = 0;

// Loop through all page items in the document
for (var i = 0; i < doc.pageItems.length; i++) {
var currentItem = doc.pageItems[i];
totalArea += calculateArea(currentItem);
}

// Display the total area
alert("Total Fill Color Area: " + totalArea.toFixed(2) + " square units");
}

// Run the main function
calculateTotalArea();