30-seconds-of-code/snippets/zip.md

title, tags, cover, firstSeen, lastUpdated

title	tags	cover	firstSeen	lastUpdated
Group array elements	array	orange-flower	2017-12-17T16:41:31+02:00	2020-10-22T20:24:44+03:00

Creates an array of elements, grouped based on their position in the original arrays.

• Use Math.max(), Function.prototype.apply() to get the longest array in the arguments.
• Create an array with that length as return value and use Array.from() with a mapping function to create an array of grouped elements.
• If lengths of the argument arrays vary, undefined is used where no value could be found.

const zip = (...arrays) => {
  const maxLength = Math.max(...arrays.map(x => x.length));
  return Array.from({ length: maxLength }).map((_, i) => {
    return Array.from({ length: arrays.length }, (_, k) => arrays[k][i]);
  });
};

zip(['a', 'b'], [1, 2], [true, false]); // [['a', 1, true], ['b', 2, false]]
zip(['a'], [1, 2], [true, false]); // [['a', 1, true], [undefined, 2, false]]