Merge multiple array in lodash

Question

I want to merge these array in to single array with unique value. don't want repeated values.

0:Array(2) ["General Fitness", "Health & Fitness"]
1:Array(2) ["Cardiovascular", "Meditation"]
2:Array(3) ["Health & Fitness", "Cardiovascular", "General Fitness"]
3:Array(1) ["Cardiovascular"]

I am expecting this answer:

["General Fitness", "Health & Fitness", "Cardiovascular", "Meditation"]

Possible duplicate of [How to merge two array of object by using lodash?](https://stackoverflow.com/questions/38612972/how-to-merge-two-array-of-object-by-using-lodash) — Anshul Verma, Apr 04 '18 at 13:10
_(data.hits.hits).map('_source.topics').compact().value() @ChrisR — Saad Ahmed, Apr 04 '18 at 13:11

Ori Drori · Accepted Answer · 2020-11-10T01:09:19.530

With lodash you can use _.union() and _.spread() to generate a function that flattens to a single array with unique values:

const fn = _.spread(_.union);

const arrs = [ 
  ["General Fitness", "Health & Fitness"],
  ["Cardiovascular", "Meditation"],
  ["Health & Fitness", "Cardiovascular", "General Fitness"],
  ["Cardiovascular"]
];

const result = fn(arrs);

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js"></script>

Using ES6 you can flatten the arrays, and make the result unique by passing it through a Set, and spreading back to an array:

const arrs = [ 
  ["General Fitness", "Health & Fitness"],
  ["Cardiovascular", "Meditation"],
  ["Health & Fitness", "Cardiovascular", "General Fitness"],
  ["Cardiovascular"]
];

const result = [...new Set(arrs.flat())];

console.log(result);

score 9 · Answer 2 · answered Apr 04 '18 at 13:16

const arrs = [ 
  ["General Fitness", "Health & Fitness"],
  ["Cardiovascular", "Meditation"],
  ["Health & Fitness", "Cardiovascular", "General Fitness"],
  ["Cardiovascular"]
];

const result = _.uniq(_.flatten(arrs));

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js"></script>

score 4 · Answer 3 · answered Apr 04 '18 at 13:19

use union

var object =  ["General Fitness", "Health & Fitness"];
var other =  ["Cardiovascular", "Health & Fitness", "Meditation"]
 
_.union(object, other);

// ["General Fitness", "Health & Fitness", "Cardiovascular", "Meditation"]

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js"></script>

score 0 · Answer 4 · answered Apr 01 '23 at 13:06

Simply use lodash flatten method:

const arrs = [ 
  ["General Fitness", "Health & Fitness"],
  ["Cardiovascular", "Meditation"],
  ["Health & Fitness", "Cardiovascular", "General Fitness"],
  ["Cardiovascular"]
];

result = _.flatten(arrs);

console.log(result);

Merge multiple array in lodash

4 Answers4