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30-seconds-of-code/javascript/snippets/to-hash.md
2023-05-01 22:35:56 +03:00

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---
title: Iterable to hash
type: snippet
tags: [array]
cover: sleepy-cat
dateModified: 2022-01-30T12:45:30+03:00
---
Reduces a given iterable into a value hash (keyed data store).
- Use `Object.values()` to get the values of the iterable (object or array).
- Use `Array.prototype.reduce()` to iterate over the values and create an object, keyed by the reference value.
```js
const toHash = (object, key) =>
Object.values(object).reduce((acc, data, index) => {
acc[!key ? index : data[key]] = data;
return acc;
}, {});
```
```js
toHash([4, 3, 2, 1]); // { 0: 4, 1: 3, 2: 2, 3: 1 }
toHash([{ a: 'label' }], 'a'); // { label: { a: 'label' } }
```