Function getFirstOrError

front_end/testing/InsightHelpers.ts:93–100

(iterator: IterableIterator<T>)

}

export function getFirstOrError<T>(iterator: IterableIterator<T>): T {
  const result = iterator.next();
  if (result.done || result.value === undefined) {
    throw new Error('iterator has zero values');
  }

  return result.value;
}

export function getFirst<T>(iterator: IterableIterator<T>): T|undefined {
  return iterator.next().value;