Simple form that shows field value and clears field on button click. Tracks input to text and uses its value at the time of the button click and to update the state that the view is driven from.

Motorcycle_Clear_Input_Function_of_State.js

//http://www.webpackbin.com/N1KplM91b
import Motorcycle from '@motorcycle/core'
import {div, label, input, hr, h1, makeDOMDriver} from '@motorcycle/dom';
import most from 'most'

function main(sources) {
  
  const input$ = sources.DOM.select('.field').events('input')
  
  const nameChange$ = input$
    .map(ev => ({displayName:'', inputVal:ev.target.value}))
  
  const click$ = sources.DOM.select('.btn').events('click')
  
  const save$ = input$.sampleWith(click$)
    .map(ev => ({displayName:ev.target.value, inputVal:''}))
  
  const state$ = nameChange$.merge(save$).startWith({displayName:''})
  
  const sinks = {
    DOM: state$
      .map(function(obj){
        return div([
          label('Name:'),
          input('.field', {attrs: {type: 'text'}, props:{ 
                                   value: obj.inputVal}}),
          input('.btn', {attrs:{type:'submit',value:'Save'}}),
          hr(),
          h1('Hello ' + obj.displayName)
        ])
      })
  };
  return sinks;
}

Motorcycle.run(main, { DOM: makeDOMDriver('#app') });