defaultTTL.ts

import { CachedValue, IMinimalResponse } from './types';

export default function defaultTTL<ResponseT extends IMinimalResponse>(
  cachedValue: CachedValue<ResponseT>
) {
  switch (cachedValue.state) {
    case 'running':
      // Evict running promises after 30s if they are not resolved to allow re-requesting.
      // This leaves it up to the fetch implementation to clean up resources if requests are not
      // aborted and the same URL is requested multiple times.
      return 30000;

    case 'resolved':
      const { response } = cachedValue;
      // Keep successful or 'resource missing' responses in the cache for 120 minutes
      if (response && (response.status === 200 || response.status === 404)) {
        return 120 * 60 * 1000;
      }
      // Allow retrying all other responses after 10 seconds
      return 10000;

    case 'rejected':
      const { error } = cachedValue;
      if (typeof error.name !== 'undefined' && error.name === 'AbortError') {
        return 0;
      }
      // Allow reattempting failed requests after 10 seconds
      return 10000;
  }
}