Function addItemToEnvelope

packages/core/src/utils/envelope.ts:37–40

(envelope: E, newItem: E[1][number])

 * so that the envelope types resolve correctly.
 */
export function addItemToEnvelope<E extends Envelope>(envelope: E, newItem: E[1][number]): E {
  const [headers, items] = envelope;
  return [headers, [...items, newItem]] as unknown as E;
}

/**
 * Convenience function to loop through the items and item types of an envelope.