Merge Array of Objects by Property using Lodash

Question

I have two arrays of objects that represent email addresses that have a label and a value:

var original = [
  {
    label: \'private\',
    value: \'private@         


        

Answer 1

Convert the lists to objects keyed by label, merge them by _.assign, and convert it back to an array. It will even retain order of the items on most browsers.

var original = [
  {
    label: 'private',
    value: 'private@johndoe.com'
  },
  {
    label: 'work',
    value: 'work@johndoe.com'
  }
];

var update = [
  {
    label: 'private',
    value: 'me@johndoe.com'
  },
  {
    label: 'school',
    value: 'schol@johndoe.com'
  }
];

console.log(
  _.map(
    _.assign(
      _.mapKeys(original, v => v.label),
      _.mapKeys(update, v => v.label)
    )
  )
);


// or remove more duplicated code using spread

console.log(
  _.map(
    _.assign(
      ...[original, update].map(
        coll => _.mapKeys(coll, v => v.label)
      )
    )
  )
);