Example usage

npm install create-element-class --save-dev

const createElementClass = require('create-element-class')

const HelloWorld = createElementClass({
  attributeChangedCallback(name, oldValue, newValue) {},
  connectedCallback() {},
  disconnectedCallback() {}
})
HelloWorld.observedAttributes: ['foo', 'bar'],

customElements.define('hello-world', HelloWorld)

Credit

Thank you, Andy VanWagoner, for giving me permission to publish this after-hours experiment of yours.