Function typeMapGet

src/ytype.js:1799–1803

(parent, key)

 * @function
 */
export const typeMapGet = (parent, key) => {
  parent.doc ?? warnPrematureAccess()
  const val = parent._map.get(key)
  return val !== undefined && !val.deleted ? val.content.getContent()[val.length - 1] : undefined
}

/**
 * @param {YType<any>} parent