Reset All Text Styles in Google Docs Using Google Apps Script

function resetTextStyles() {
  const doc = DocumentApp.getActiveDocument();
  const body = doc.getBody();
  const paragraphs = body.getParagraphs();

  paragraphs.forEach(paragraph => {
    const text = paragraph.editAsText();
    if (text) {
      // Remove bold and italic styles for the entire paragraph
      text.setBold(false);
      text.setItalic(false);
    }
  });
}