code: function StepperView(vm, stepper) {
  	function add(num) {
  		stepper.value += num;
  		vm.redraw();
  	}
  
  	function set(e) {
  		stepper.value = +e.target.value;
  	}
  
  	// template renderer (called on each redraw)
  	return function() {
  		return el("#stepper", [
  			el("button", {onclick: [add, -1]}, "-"),
  			el("input[type=number]", {value: stepper.value, oninput: set}),
  			el("button", {onclick: [add, +1]}, "+"),
  		]);
  	};
  }
docs: view closure (called once during init)