Google Sheet script that will convert cells A2:N1000 into a downloadable XML file.

products.js

/* Main function for generating XML from spreadsheet. */
function doGet() {
  // The sheet that contains the product information.
  var productDataSheet = SpreadsheetApp.getActiveSpreadsheet().getSheetByName("Products");
  // The first row of the sheet that contains all the product attributes (e.g., Color, Weight, Collection, Name, etc.)
  var productAttributes = productDataSheet.getRange("A1:N1").getValues();
  // Range of rows and columns that contain the product information.
  var productData = productDataSheet.getRange("A2:N1000").getValues();
  // XML document object.
  var document = XmlService.createDocument();
  // Root element of the XML output.
  var root = XmlService.createElement('products');
  // variable that holds the generated XML document.
  var xmlOutput;
  
  for(var i = 0; i < productData.length; i++) {
    
    if(!isEnd(productData[i])) {
      
      // Begin product tag.
      var product = XmlService.createElement('product');
      
      // Start iterating through each of the product's attributes.
      for(var j = 0; j < productData[i].length; j++) {
        
        var tag = productAttributes[0][j];
        var text = productData[i][j];
        
        if(tag == "categories") {
          
          product.addContent(createCategories(text));
          
        } else if( tag == "images") {
          
          product.addContent(createImages(text));
          
        } else if(tag == "collections_styles") {
          
          product.addContent(createCollectionStyles(text));
          
        } else {
          
          var productAttribute = XmlService.createElement(tag)
          
          if(tag == "description") {
            
            productAttribute.addContent(XmlService.createCdata(text));
            
          } else {
            
            productAttribute.setText(text);
            
          }
          
          product.addContent(productAttribute)
          
        }
        
      }
      
      root.addContent(product);
      
    } else {
      
      break;
      
    }
  }
  
  // Put everything together and output it.
  document.addContent(root);
  xmlOutput = XmlService.getPrettyFormat().format(document);
  return ContentService.createTextOutput(xmlOutput).downloadAsFile("products.xml");
}

/* Helper function for creating child tags for each category. */
function createCategories(categories) {
  
  var elCategories = XmlService.createElement("categories");
  
  // Clean up category name.
  var categories = categories.replace(/_/g, " ").replace(/:/g, ",").split(',');
  
  for(var i = 0; i < categories.length; i++) {
    
    var elCategory = XmlService.createElement("category");
    
    elCategory.setText(categories[i]);
    elCategories.addContent(elCategory);
    
  }
  
  return elCategories;
  
}

/* Helper function for creating child tags for images. */
function createImages(images) {
  
  var elImages = XmlService.createElement("images");
  var images = images.split(",");
  
  for(var i = 0; i < images.length; i++) {
  
    var elImage = XmlService.createElement("image");
    
    elImage.setText(images[i]);
    elImages.addContent(elImage);
  
  }
  
  return elImages;
  
}

/* Helper function for creating child tags for collections and styles. */
function createCollectionStyles(collections_styles) {
  
  var elCollectionStyles = XmlService.createElement("collections_styles");
  var collections = collections_styles.split(",");
  
  for(var i = 0; i < collections.length; i++) {
    
    var elCollectionStyle = XmlService.createElement("collection_style");
    
    elCollectionStyle.setText(collections[i]);
    elCollectionStyles.addContent(elCollectionStyle);
    
  }
  
  return elCollectionStyles;
  
}

function isEnd(row) {
  
  for(var i = 0; i < row.length; i++) {
    
    if(row[i] != "") {
      
      return false;
      
    }
    
  }
  
  return true;
}