Install:

yarn

Compile:

./render.sh

See sample components at mjml-components/lmc-button.js and mjml-components/lmc-image.js - they are a clone of <mj-button> and <mj-image> with added data-msys-linkname property.

What was needed was to specify dependencies, like this:

import { registerDependencies } from 'mjml-validator'

registerDependencies({
	// which components can contain image
  'mj-column': ['lmc-image'],
  // 'mj-something-else': ['lmc-image'],

	// image can contain no components
  'lmc-image': []
});