app/frontend/javascript/state_change_reasons.js
import $ from 'jquery'
let updateDisplay = function (new_state, speed) {
$('.reason')
.not('#' + new_state + '_reasons')
.slideUp(speed)
$('#' + new_state + '_reasons').slideDown(speed)
}
let displayReason = function () {
updateDisplay(this.value, 'fast')
}
$(function () {
$('#state-changer').find('input[type=radio]').on('change', displayReason)
})