merge 2 arrays lodash code example

Example 1: how to merge 2 object array by the same key with lodash

Lodash
var a = [
  { userId:"p1", item:1},
  { userId:"p2", item:2},
  { userId:"p3", item:4}
];

var b = [
  { userId:"p1", profile:1},
  { userId:"p2", profile:2},
  { userId:"p4", profile:4}
];
var merged = _.merge(_.keyBy(a, 'userId'), _.keyBy(b, 'userId'));
var values = _.values(merged);
console.log(values);
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Example 2: lodash merge

import merge from 'lodash/merge'

let object = {  'a': [{ 'b': 2 }, { 'd': 4 }]}; 
let other = {  'a': [{ 'c': 3 }, { 'e': 5 }]}; 
merge(object, other); // => { 'a': [{ 'b': 2, 'c': 3 }, { 'd': 4, 'e': 5 }] }

Example 3: lodash merge array of objects without duplicates

var c = _.map(a, function(obj) {
    return _.assign(obj, _.find(b, {parentId: obj.aId}));
})