Common sorted list: Difference between revisions

=={{header|JavaScript}}==

<lang javascript>(() => {

"use strict";

// --------------- COMMON SORTED LIST ----------------

// commonSorted :: Ord a => [[a]] -> [a]

const commonSorted = xs =>

sort(nub(concat(xs)));

// ---------------------- TEST -----------------------

const main = () =>

commonSorted([

[5, 1, 3, 8, 9, 4, 8, 7],

[3, 5, 9, 8, 4],

[1, 3, 7, 9]

]);

// --------------------- GENERIC ---------------------

// concat :: [[a]] -> [a]

const concat = xs => [].concat(...xs);

// nub :: [a] -> [a]

const nub = xs => [...new Set(xs)];

// sort :: Ord a => [a] -> [a]

const sort = xs =>

// An (ascending) sorted copy of xs.

xs.slice().sort();

return main();

})();</lang>

{{Out}}

<pre>[1, 3, 4, 5, 7, 8, 9]</pre>