prismic-htmlSerializer.js

var htmlSerializer = function (element, content) {
  // Don't wrap images in a <p> tag
  if (element.type == "image") {
    return '<img src="' + element.url + '" alt="' + element.alt + '">';
  }

  // Add a class to hyperlinks
  if (element.type == "hyperlink") {
    return '<a class="some-link" href="' + element.url + '">' + content + '</a>';
  }

  // Return null to stick with the default behavior
  return null;
};
var html = doc.getStructuredText('blog-post.body').asHtml(getLinkResolver(), htmlSerializer);