gissue-2058.js

const _KEY = '__key__'

const DS = require('@google-cloud/datastore')()

const TABLE = 'Members10'

function getAuThoB(hash_) {
  return Promise.resolve().then(function () {
    const ret = {}
    ret.role = true
    return ret
  })
}

tstSave()

function tstSave() {
  const dat = {
    id: '57292010259742702'
  }

  return getAuThoB('aa')
    .then(function(autho) {
      return save(dat.id, dat, autho)
    })
}

function save(id, jDObj) {
  const ipro = _save(TABLE, id, jDObj)
  return ipro
}

function  _makeKey(table_, id) {
  const k = DS.key([
    table_,
    Number(id)
  ])
  return k
}

function _save(table_, id, jDObj) {
  const key = _makeKey(table_, id)

  const jD = jDObj
  jD.id = id

  return DS.get(key)
    .then(function(data) {
      const row = data[0]

      return DS.update({
        key: key,
        data: Object.assign(row, jD)
      })
    })
    .then(function(res) {
      return res[0].mutationResults[0]
    })
    .catch(function(er){
      console.log('_save er '+ er)
    })
}