Ungroup array elements

OSCC · JavaScript, Array · Oct 22, 2020

Creates an array of arrays, ungrouping the elements in an array produced by zip.

  • Use Math.max(), Function.prototype.apply() to get the longest subarray in the array, Array.prototype.map() to make each element an array.
  • Use Array.prototype.reduce() and Array.prototype.forEach() to map grouped values to individual arrays.
const unzip = arr =>
  arr.reduce(
    (acc, val) => (val.forEach((v, i) => acc[i].push(v)), acc),
    Array.from({
      length: Math.max(...arr.map(x => x.length))
    }).map(x => [])
  );
unzip([['a', 1, true], ['b', 2, false]]); // [['a', 'b'], [1, 2], [true, false]]
unzip([['a', 1, true], ['b', 2]]); // [['a', 'b'], [1, 2], [true]]

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