How to get new Set from array of arrays by using Array.map function?

Question

Exploring Sets now and could not get a new Set from an array of x arrays in it. I what to use Array.map method inside new Set().

Here is what I'm trying to do, and it seems logical, but in the end having values only from the 1st array:

new Set(...array.map(x => x.value));

Will be awesome to understand what I am doing wrong and how it should look like

Update: To be more clear in my need:

const array = [[1,1,3,4], [2,2,3,4], [1,1,3,5]];
new Set(...array.map(x => x));

My goal to have [1,2,3,4,5] but getting [1,3,4]

Solution:

 new Set(array.map(x => x.value).flat())

Nina Scholz · Accepted Answer · 2022-04-07 08:44:07Z

1

You need only the array, not spreaded parameters:

new Set(array.map(x => x.value));

From Set:

Syntax

new Set()
new Set(iterable)

With a nested array, you need a flat it first:

const
    array = [[1, 1, 3, 4], [2, 2, 3, 4], [1, 1, 3, 5]],
    unique = new Set(array.flat()),
    result = [...unique].sort((a, b) => a - b);

console.log(...unique); // still a set
console.log(...result); // array, sorted

edited Apr 7, 2022 at 8:44

answered Apr 7, 2022 at 8:32

Nina Scholz

388k26 gold badges367 silver badges417 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

kadeikin Over a year ago

Sorry, maybe incorrectly described my goal. I think that will be better: const array = [[1,1,3,4], [2,2,3,4], [1,1,3,5]]; new Set(...array.map(x => x)); I want [1,2,3,4,5] in the end, but getting [1,3,4].

Collectives™ on Stack Overflow

How to get new Set from array of arrays by using Array.map function?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related