Best way of concatenating array of arrays and integers

Question

Given an array of different elements, arrays and integers, I would like to come up with an array of all the integers contained in the array:

x= [[ 1,2,3], 4, [5,6], 7, 8, [9]]
pretty(x) -> [1,2,3,4,5,6,7,8,9];

I did manage to complete it with a rather ugly reduce, but I'd like to know if there is something prettier to do with it:

x.reduce((t, e) => {
        if (!e instanceof Array) [e];
        return t.concat(e);
    });

Any recommendation?

Thanks!

The `!e instanceof Array` statement will always be `false` because the `!` created a `boolean` which will never be an `Array`. Use `!(e instanceof Array)` instead. — Titus, Aug 24 '20 at 18:17

Majed Badawi · Accepted Answer · 2020-08-25T09:09:55.927

4

x= [[ 1,2,3], 4, [5,6], 7, 8, [9]]
x = x.flat(Infinity);
console.log(...x);
x = [[[1, 2, 3]]];
x = x.flat(Infinity);
console.log(...x);

edited Aug 25 '20 at 09:09

answered Aug 24 '20 at 18:16

Majed Badawi

Notice that this solution flattens only one layer of nested arrays: `[[[1, 2, 3]]].flat()` returns `[[1, 2, 3]]` – Shay Yzhakov Aug 25 '20 at 08:36

1 Answers1