30-seconds-of-code/snippets/js/s/to-hash.md

title, type, language, tags, cover, dateModified

title	type	language	tags	cover	dateModified
Iterable to hash	snippet	javascript	array	sleepy-cat	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.

const toHash = (object, key) =>
  Object.values(object).reduce((acc, data, index) => {
    acc[!key ? index : data[key]] = data;
    return acc;
  }, {});

toHash([4, 3, 2, 1]); // { 0: 4, 1: 3, 2: 2, 3: 1 }
toHash([{ a: 'label' }], 'a'); // { label: { a: 'label' } }