richtext.js

const PrismicRichText = require('@prismicio/richtext');
const { Link: LinkHelper } = require('@prismicio/helpers');
const escapeHtml = require('escape-html');

const { Elements } = PrismicRichText;

function serialize(linkResolver, type, element, content, children) {
  switch(type) {
    case Elements.heading1: return serializeStandardTag('h1', element, children);
    case Elements.heading2: return serializeStandardTag('h2', element, children);
    case Elements.heading3: return serializeStandardTag('h3', element, children);
    case Elements.heading4: return serializeStandardTag('h4', element, children);
    case Elements.heading5: return serializeStandardTag('h5', element, children);
    case Elements.heading6: return serializeStandardTag('h6', element, children);
    case Elements.paragraph: return serializeStandardTag('p', element, children);
    case Elements.preformatted: return serializePreFormatted(element);
    case Elements.strong: return serializeStandardTag('strong', element, children);
    case Elements.em: return serializeStandardTag('em', element, children);
    case Elements.listItem: return serializeStandardTag('li', element, children);
    case Elements.oListItem: return serializeStandardTag('li', element, children);
    case Elements.list: return serializeStandardTag('ul', element, children);
    case Elements.oList: return serializeStandardTag('ol', element, children);
    case Elements.image: return serializeImage(linkResolver, element);
    case Elements.embed: return serializeEmbed(element);
    case Elements.hyperlink: return serializeHyperlink(linkResolver, element, children);
    case Elements.label: return serializeLabel(element, children);
    case Elements.span: return serializeSpan(content);
    default: return '';
  }
}

function label(element) {
  return element.label ? ` class="${element.label}"` : '';
}

function serializeStandardTag(tag, element, children) {
  return `<${tag}${label(element)}>${children.join('')}</${tag}>`;
}

function serializePreFormatted(element) {
  return `<pre${label(element)}>${escapeHtml(element.text)}</pre>`;
}

function serializeImage(linkResolver, element) {
  const linkUrl = element.linkTo ? LinkHelper.url(element.linkTo, linkResolver) : null;
  const linkTarget = element.linkTo && element.linkTo.target ? `target="${element.linkTo.target}" rel="noopener"` : '';
  const wrapperClassList = [element.label || '', 'block-img'];
  const img = `<img src="${element.url}" alt="${element.alt ? escapeHtml(element.alt) : ''}" copyright="${element.copyright ? escapeHtml(element.copyright) : ''}" />`;

  return (`
    <p class="${wrapperClassList.join(' ')}">
      ${linkUrl ? `<a ${linkTarget} href="${linkUrl}">${img}</a>` : img}
    </p>
  `);
}

function serializeEmbed(element) {
  return (`
    <div data-oembed="${element.oembed.embed_url}"
      data-oembed-type="${element.oembed.type}"
      data-oembed-provider="${element.oembed.provider_name}"
      ${label(element)}>

      ${element.oembed.html}
    </div>
  `);
}

function serializeHyperlink(linkResolver, element, children) {
  const target = element.data.target ? `target="${element.data.target}" rel="noopener"` : '';
  const url = escapeHtml(LinkHelper.url(element.data, linkResolver));
  return `<a ${target} href="${url}">${children.join('')}</a>`;
}

function serializeLabel(element, children) {
  return `<span ${label(element.data)}>${children.join('')}</span>`;
}

function serializeSpan(content) {
  return content ? escapeHtml(content).replace(/\n/g, '<br />') : '';
}

module.exports = {
  asText(structuredText, joinString) {
    return PrismicRichText.asText(structuredText, joinString);
  },

  asHtml(richText, linkResolver, htmlSerializer) {
    const serialized = PrismicRichText.serialize(richText, serialize.bind(null, linkResolver), htmlSerializer);
    return serialized.join('');
  },

  Elements : Elements
};