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javascript/snippets/unzip.md

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+---
+title: Ungroup array elements
+type: snippet
+tags: [array]
+cover: glass-blowing
+dateModified: 2020-10-22T20:24:44+03:00
+---
+
+Creates an array of arrays, ungrouping the elements in an array produced by [zip](/js/s/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.
+
+```js
+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 => [])
+  );
+```
+
+```js
+unzip([['a', 1, true], ['b', 2, false]]); // [['a', 'b'], [1, 2], [true, false]]
+unzip([['a', 1, true], ['b', 2]]); // [['a', 'b'], [1, 2], [true]]
+```