serialize-localstorage-form.js

import serializeForm from 'form-serialize'

const getLocalStorage = (key) => {
  let data = null
  try { data = JSON.parse(localStorage[key]) } catch() {}
  return data
}

const setLocalStorage = (key, data) => {
  localStorage[key] = JSON.stringify(data)
}

class Form extends React.Component {
  constructor({ route }, { router }) {
    super()
    this.state = { formData: getLocalStorage('whatever') || {} }
    router.setRouteLeaveHook(route, () => {
      setLocalStorage('whatever', serializeForm(findDOMNode(this)))
    })
  }
}

Form.contextTypes = { router: React.PropTypes.object }