@vis.gl/react-google-maps/src/libraries/assert-not-null.ts

React components and hooks for the Google Maps JavaScript API

/**
 * A typescript assertion function used in cases where typescript has to be
 * convinced that the object in question can not be null.
 *
 * @param value
 * @param message
 */
export function assertNotNull<TValue>(
  value: TValue,
  message = 'assertion failed'
): asserts value is NonNullable<TValue> {
  if (value === null || value === undefined) {
    throw Error(message);
  }
}