Userinterface.js – A small library to build front-end JavaScript applications(github.com)

  UserInterface.model({
   name: "children",
   method: UserInterface.appendChild,
   properties: {
    tagName: "div",
    className: "model",
    children: [
     {
      tagName: "div",
      className: "child",
      textContent: "My first child"
      // and so on..
     }
    ]
   }
  });

    h('div.model', [
      h('div.child', 'My first child')
    ])

   <div class="model">
     <div class="child">My first child</div>
   </div>

    function h(tagName, attributes, ...children) {
      return {
        tagName,
        ...attributes,
        children
      }
    }

  UserInterface.model({
   name: "children",
   method: UserInterface.appendChild,
   properties: (
     h('div', { className: 'model' }, [
      h('div', {
        className: 'child',
        textContent: 'My first child'
      })
    ])
   )
  });