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javascript/snippets/powerset.md

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+---
+title: Powerset
+type: snippet
+tags: [math,algorithm]
+cover: new-plant
+dateModified: 2021-09-27T15:27:07+02:00
+---
+
+Returns the powerset of a given array of numbers.
+
+- Use `Array.prototype.reduce()` combined with `Array.prototype.map()` to iterate over elements and combine into an array containing all combinations.
+
+```js
+const powerset = arr =>
+  arr.reduce((a, v) => a.concat(a.map(r => r.concat(v))), [[]]);
+```
+
+```js
+powerset([1, 2]); // [[], [1], [2], [1, 2]]
+```