Lodash union of arrays of objects

Question

I\'d like to use the _.union function to create a union of two arrays of objects. Union works with arrays of primitives only as it uses === to examine if two va

Answer 1

lodash merge object from arrays

const test1 = [
  { name: 'zhanghong', age: 32, money: 0, size: 12, },
  { name: 'wanghong', age: 20, size: 6 },
  { name: 'jinhong', age: 16, height: 172 },
]

const test2 = [
  { name: 'zhanghong', gender: 'male', age: 14 },
  { name: 'wanghong', gender: 'female', age: 33 },
  { name: 'lihong', gender: 'female', age: 33 },
]

const test3 = [
  { name: 'meinv' },
]

const test4 = [
  { name: 'aaa' },
]

const test5 = [
  { name: 'zhanghong', age: 'wtf' },
]

const result = mergeUnionByKey(test1, test2, test3, test4, [], test5, 'name', 'override')

function mergeUnionByKey(...args) {

  const config = _.chain(args)
    .filter(_.isString)
    .value()

  const key = _.get(config, '[0]')

  const strategy = _.get(config, '[1]') === 'override' ? _.merge : _.defaultsDeep

  if (!_.isString(key))
    throw new Error('missing key')

  const datasets = _.chain(args)
    .reject(_.isEmpty)
    .filter(_.isArray)
    .value()

  const datasetsIndex = _.mapValues(datasets, dataset => _.keyBy(dataset, key))

  const uniqKeys = _.chain(datasets)
    .flatten()
    .map(key)
    .uniq()
    .value()

  return _.chain(uniqKeys)
    .map(val => {
      const data = {}
      _.each(datasetsIndex, dataset => strategy(data, dataset[val]))
      return data
    })
    .filter(key)
    .value()

}

console.log(JSON.stringify(result, null, 4))