27 lines
721 B
Markdown
27 lines
721 B
Markdown
---
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title: Iterable to hash
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tags: array
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expertise: intermediate
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cover: blog_images/sleepy-cat.jpg
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firstSeen: 2018-05-31T02:14:04+03:00
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lastUpdated: 2022-01-30T12:45:30+03:00
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---
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Reduces a given iterable into a value hash (keyed data store).
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- Use `Object.values()` to get the values of the iterable (object or array).
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- Use `Array.prototype.reduce()` to iterate over the values and create an object, keyed by the reference value.
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```js
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const toHash = (object, key) =>
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Object.values(object).reduce((acc, data, index) => {
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acc[!key ? index : data[key]] = data;
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return acc;
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}, {});
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```
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```js
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toHash([4, 3, 2, 1]); // { 0: 4, 1: 3, 2: 2, 3: 1 }
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toHash([{ a: 'label' }], 'a'); // { label: { a: 'label' } }
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```
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