How to programmatically clear PaperInput and have the floating label drop down to the input line

Question

I have the following markup:

Answer 1

It seems you need to call blur on the actual <input id='input'> element inside <paper-input> not the <paper-input> itself.
I got it working with

import 'dart:js' as js;

var inp = $['alias-input'] as PaperInput;
inp.inputValue = '';
new js.JsObject.fromBrowserObject(inp).callMethod('inputBlurAction', []);

alternatively you can do it like

var inp = $['alias-input'] as PaperInput;
inp.inputValue = '';
inp.querySelector('* /deep/ #input') // not yet supported with polyfills
..focus() // blur doesn't work when the field doesn't have the focus
..blur();