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Function: keys()

Returns an iterable containing the keys of object.

This differs from Map.prototype.keys in that the returned iterable can be iterated multiple times and differs from Object.keys in that the returned iterable is opaque.

Example​

import { keys, pipe, reduce, toArray } from 'lfi'

console.log(
  pipe(
    keys([`sloth`, `lazy`, `sleep`]),
    reduce(toArray()),
  ),
)
//=> [ 0, 1, 2 ]

console.log(
  pipe(
    keys({
      sloth: 1,
      lazy: 2,
      sleep: 3,
    }),
    reduce(toArray()),
  ),
)
//=> [ 'sloth', 'lazy', 'sleep' ]

console.log(
  pipe(
    keys(
      new Map([
        [`sloth`, 1],
        [`lazy`, 2],
        [`sleep`, 3],
      ]),
    ),
    reduce(toArray()),
  ),
)
//=> [ 'sloth', 'lazy', 'sleep' ]
Playground

Since​

v0.1.0

Call Signature​

keys<Key>(object): Iterable<Key, any, any>

Type Parameters​

• Key

Parameters​

object​

ReadonlyMap<Key, unknown>

Returns​

Iterable<Key, any, any>

Defined in​

generators.d.ts:57

Call Signature​

keys<Key>(object): Iterable<Key, any, any>

Type Parameters​

• Key extends PropertyKey

Parameters​

object​

Readonly<Record<Key, unknown>>

Returns​

Iterable<Key, any, any>

Defined in​

generators.d.ts:58