keyBy

Creates an object keyed by the return value of keyFn. When valueFn is passed, its return value is used as the value instead of the item itself. Each key keeps only one value, and later items override earlier ones with the same key. Use groupBy if all items under a key are needed.

Usage

import { keyBy } from 'rattail'

const users = [
  { uuid: 'a', name: 'Alice' },
  { uuid: 'b', name: 'Bob' },
]

keyBy(users, (user) => user.uuid)
// return { a: { uuid: 'a', name: 'Alice' }, b: { uuid: 'b', name: 'Bob' } }
keyBy(
  users,
  (user) => user.uuid,
  (user) => user.name,
)
// return { a: 'Alice', b: 'Bob' }

Arguments

Arg	Type	Defaults
arr	Array
keyFn	(item: any, index: number) => PropertyKey
valueFn	(item: any, index: number) => any	item itself

Return

Type
object