RosettaCodeData/Task/Loop-over-multiple-arrays-s.../JavaScript/loop-over-multiple-arrays-s...

34 lines
841 B
JavaScript

(() => {
'use strict';
// GENERIC FUNCTIONS -----------------------------------------------------
// concat :: [[a]] -> [a]
const concat = xs =>
xs.length > 0 ? (() => {
const unit = typeof xs[0] === 'string' ? '' : [];
return unit.concat.apply(unit, xs);
})() : [];
// map :: (a -> b) -> [a] -> [b]
const map = (f, xs) => xs.map(f);
// transpose :: [[a]] -> [[a]]
const transpose = xs =>
xs[0].map((_, col) => xs.map(row => row[col]));
// unlines :: [String] -> String
const unlines = xs => xs.join('\n');
// TEST ------------------------------------------------------------------
const xs = [
['a', 'b', 'c'],
['A', 'B', 'C'],
[1, 2, 3]
];
return unlines(
map(concat, transpose(xs))
);
})();