postProcessByHtml Plugin Type

Overview

A render plugin is used to transform the rendered HTML.
After the Angular application renders, the HTML content is passed to a render plugin where it can be further modified.

A render plugin could be used to transform a page containing markdown into a page that renders it.

Interface

A postProcessByHtml plugin is a function that returns a Promise<String>. The string in the promise must be the transformed HTML. The interface looks like this:

function exampleContentPlugin(
  HTML: string,
  route: HandledRoute
): Promise<string> {
  // Must return a promise
}

Making A postProcessByHtml Plugin

The following postProcessByHtml plugin example adds a title to the header to a page if it does not find one.

const { registerPlugin } = require('@scullyio/scully');

function defaultTitlePlugin(html, route) {
  // If no title in the document
  if (html.indexOf('<title') < 0) {
    const splitter = '</head>';
    const [begin, end] = html.split(splitter);
    const defaultTitle = `<title>The Truth Is Out There!</title>`;
    return Promise.resolve(`${begin}${defaultTitle}${splitter}${end}`);
  }
  return Promise.resolve(html);
}

// DON NOT FORGET REGISTER THE PLUGIN
const validator = async (conf) => [];
registerPlugin(
  'postProcessByHtml',
  'defaultTitle',
  defaultTitlePlugin,
  validator
);

module.exports.defaultTitlePlugin = defaultTitlePlugin;

In the above example, the Angular app's HTML content is transformed to include a title because anyone was found.

The next example replaces any instances of :) with an smiley emoji.

const { registerPlugin } = require('@scullyio/scully');

function smileEmojiPlugin(html, route) {
  return Promise.resolve(html.replace(/\:\)/g, '😊'));
}
// DON NOT FORGET REGISTER THE PLUGIN
const validator = async (conf) => [];
registerPlugin('postProcessByHtml', 'smiles', smileEmojiPlugin, validator);

module.exports.smileEmojiPlugin = smileEmojiPlugin;