spec/frontend/html_string_serializer.js

/**
 * This script is copied from gitlab-ui:
 * https://gitlab.com/gitlab-org/gitlab-ui/-/blob/main/tests/html_string_serializer.js
 */

export function test(received) {
  // TODO, maybe there's a better way to determine if a string is intended to be HTML
  return received && typeof received === 'string' && received.startsWith('<');
}

export function serialize(received, config, indentation, depth, refs, printer) {
  const parser = new DOMParser();
  const doc = parser.parseFromString(received, 'text/html');
  const el = doc.body.firstElementChild;

  return printer(el, config, indentation, depth, refs);
}