JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://rawgit.com/lhorie/mithril.js/next/mithril.js"></script>

JavaScript

var data = {
	nextId: 0,
	ids: []
}

var App = {
	view: function(v) {
  	return [
    	m(`button`, {
        'onclick': () => {
        	data.ids.push(data.nextId++)
        }
      },
      	`Add item`
      ),
      m(`br`),
      m(`svg`,
      	m("g", data.ids
        	.slice(-2)
          .map(id => m(`circle`, {
          		"key": id,
            	'cx': 5 + 10 * id,
              'cy': 5,
              'r': 5,
      		})
        ))
      )
    ]
  }
}

m.mount(document.body, App)