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Promises

Two adapters the platform does not ship: withTimeout and to. to returns an [error, result] tuple so a failure can be handled with an if instead of a try/catch block; try's Result is the richer, type-narrowing version of the same idea. The pass-through wrappers over Promise.all/allSettled/race, and delay, were removed in 4.0 — call the statics directly, and use sleep for a plain wait. withTimeout is a Promise.race: it rejects on time but does not cancel, so the underlying work keeps running unless it honours an AbortSignal.

Example​

import { to, withTimeout } from '@rtorcato/js-common/promises'

// Error as a value: handle failure with an `if` instead of a try/catch block.
const [err, user] = await to(getUser(id))
if (err) return reply.status(502).send('user service unavailable')
user.email

// Reject after 2s. The request itself is not cancelled — it keeps running.
await withTimeout(getUser(id), 2_000, new Error('user service slow'))

Import​

import { to, withTimeout } from '@rtorcato/js-common/promises'

Exports​

NameSummary
toWraps a promise and returns a tuple [error, result].
withTimeoutReturns a promise that rejects after a timeout if the input promise does not resolve.

See also​

  • sleep — await a fixed or random delay
  • functions — debounce, throttle, once, compose
  • try — Result tuples instead of thrown exceptions
  • abortController — cancel in-flight work with an AbortSignal