export function deepClone (oldData, newData) {
  if (newData instanceof Array) {
    if (oldData.length !== newData.length) {
      oldData = new Array(newData.length)
    }
    for (var i = 0; i < newData.length; i++) {
      if (newData[i] instanceof Array) {
        oldData[i] = new Array(newData[i].length)
        deepClone(oldData[i], newData[i])
      } else if (newData[i] instanceof Object) {
        oldData[i] = {}
        deepClone(oldData[i], newData[i])
      } else {
        oldData[i] = newData[i]
      }
    }
  } else if (newData instanceof Object) {
    if (oldData.length > 0) {
      oldData = {}
    }
    for (var key in newData) {
      if (newData[key] instanceof Array) {
        oldData[key] = new Array(newData[key].length)
        deepClone(oldData[key], newData[key])
      } else if (newData[key] instanceof Object) {
        oldData[key] = {}
        deepClone(oldData[key], newData[key])
      } else {
        oldData[key] = newData[key]
      }
    }
  }
}