Merging H3 Paragraphs with Following Text Using Google Apps Script

function appendFollowingParagraphToH3() {
  // Get the active document
  var doc = DocumentApp.getActiveDocument();
  var body = doc.getBody();
  
  // Get all the elements in the document
  var totalElements = body.getNumChildren();

  // Loop through the elements
  for (var i = 0; i < totalElements; i++) {
    var element = body.getChild(i);
    
    // Check if the element is a paragraph and if it's an H3
    if (element.getType() == DocumentApp.ElementType.PARAGRAPH) {
      var paragraph = element.asParagraph();
      if (paragraph.getHeading() === DocumentApp.ParagraphHeading.HEADING3) {
        // Check if the next element exists and is a paragraph
        if (i + 1 < totalElements) {
          var nextElement = body.getChild(i + 1);
          if (nextElement.getType() == DocumentApp.ElementType.PARAGRAPH) {
            var nextParagraph = nextElement.asParagraph();
            
            // Append the text of the next paragraph to the H3 paragraph
            paragraph.appendText(' ' + nextParagraph.getText());
            
            // Remove the next paragraph
            body.removeChild(nextParagraph);
            
            // Decrement the total elements count
            totalElements--;
          }
        }
      }
    }
  }
}