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Function: filterAsync()

Returns an async iterable that contains the values of asyncIterable in iteration order excluding the values for which fn returns a value awaitable to a falsy value.

Like Array.prototype.filter, but for async iterables.

Example​

import { asAsync, filterAsync, pipe, reduceAsync, toArray } from 'lfi'

const API_URL = `https://api.dictionaryapi.dev/api/v2/entries/en`

console.log(
  await pipe(
    asAsync([`sloth`, `lazy`, `sleep`]),
    filterAsync(async word => {
      const response = await fetch(`${API_URL}/${word}`)
      const [{ meanings }] = await response.json()
      return meanings.some(meaning => meaning.partOfSpeech === `adjective`)
    }),
    reduceAsync(toArray()),
  ),
)
//=> [ 'lazy' ]
Playground

Since​

v0.0.1

Call Signature​

filterAsync<From, To>(fn): (asyncIterable) => AsyncIterable<To, any, any>

Type Parameters​

• From

• To

Parameters​

fn​

(value) => value is To

Returns​

Function

Parameters​

asyncIterable​

AsyncIterable<From, any, any>

Returns​

AsyncIterable<To, any, any>

Defined in​

filters.d.ts:77

Call Signature​

filterAsync<From, To>(fn, asyncIterable): AsyncIterable<To, any, any>

Type Parameters​

• From

• To

Parameters​

fn​

(value) => value is To

asyncIterable​

AsyncIterable<From, any, any>

Returns​

AsyncIterable<To, any, any>

Defined in​

filters.d.ts:80

Call Signature​

filterAsync<Value>(fn): (asyncIterable) => AsyncIterable<Value, any, any>

Type Parameters​

• Value

Parameters​

fn​

(value) => unknown

Returns​

Function

Parameters​

asyncIterable​

AsyncIterable<Value, any, any>

Returns​

AsyncIterable<Value, any, any>

Defined in​

filters.d.ts:85

Call Signature​

filterAsync<Value>(fn, asyncIterable): AsyncIterable<Value, any, any>

Type Parameters​

• Value

Parameters​

fn​

(value) => unknown

asyncIterable​

AsyncIterable<Value, any, any>

Returns​

AsyncIterable<Value, any, any>

Defined in​

filters.d.ts:88