reorder.js

// Move item in an array immutably
function moveItem (array, fromIndex, toIndex) {
  console.log(`moving from ${fromIndex} to ${toIndex}`)
  const arrayCopy = array.slice()
  const item = arrayCopy[fromIndex]
  arrayCopy.splice(fromIndex, 1) // remove field that's moving
  arrayCopy.splice(toIndex, 0, item) // add it back
  return arrayCopy
}