checkAvailability

Poll a getter until a value is available (or matches an expected value), then run a callback — with timeout and configurable retry interval.

Useful for waiting on a third-party SDK to attach itself to window, on a Vue ref to be populated after mount, or on any asynchronously-available value.

Usage

import { checkAvailability } from '@maz-ui/utils'

checkAvailability(
  () => window.Stripe,
  (Stripe) => {
    const stripe = Stripe('pk_...')
  },
)

API

function checkAvailability<T>(
  getRef: () => T | null | undefined,
  callback: (value: NonNullable<T>) => void,
  options?: {
    maxAttempts?: number
    interval?: number
    expectedValue?: T
    errorMessage?: string
    onError?: (error: Error) => void
  },
): void

Option	Type	Default	Description
maxAttempts	number	20	Number of polls before giving up
interval	number	100	Delay between polls, in milliseconds
expectedValue	T	—	When set, callback fires only when getRef() strictly equals this value
errorMessage	string	—	Custom error message when maxAttempts is exceeded
onError	Function	—	Called with the timeout Error instead of throwing

With default options, the helper polls every 100 ms up to 20 times — a 2 second timeout in total.

Examples

Wait for a global SDK with a custom timeout:

checkAvailability(
  () => window.gtag,
  (gtag) => {
    gtag('event', 'page_view')
  },
  {
    maxAttempts: 50,
    interval: 200,
    onError: (err) => {
      console.warn('gtag never loaded', err)
    },
  },
)

Wait for a specific value (e.g. SDK becomes ready):

checkAvailability(
  () => window.__SDK_STATE__,
  () => boot(),
  { expectedValue: 'ready' },
)