Function orderByWithFractionalIndexBase

packages/db-ivm/src/operators/orderBy.ts:137–180

(
  topKFunction: typeof topKWithFractionalIndex,
  valueExtractor: (
    value: T extends KeyValue<unknown, infer V> ? V : never,
  ) => Ve,
  options?: OrderByWithFractionalIndexOptions<Ve>,
)

}

export function orderByWithFractionalIndexBase<
  T extends KeyValue<unknown, unknown>,
  Ve = unknown,
>(
  topKFunction: typeof topKWithFractionalIndex,
  valueExtractor: (
    value: T extends KeyValue<unknown, infer V> ? V : never,
  ) => Ve,
  options?: OrderByWithFractionalIndexOptions<Ve>,
) {
  type KeyType = T extends KeyValue<infer K, unknown> ? K : never
  type ValueType = T extends KeyValue<unknown, infer V> ? V : never

  const limit = options?.limit ?? Infinity
  const offset = options?.offset ?? 0
  const setSizeCallback = options?.setSizeCallback
  const setWindowFn = options?.setWindowFn
  const comparator =
    options?.comparator ??
    ((a, b) => {
      // Default to JS like ordering
      if (a === b) return 0
      if (a < b) return -1
      return 1
    })

  return (
    stream: IStreamBuilder<T>,
  ): IStreamBuilder<[KeyType, [ValueType, string]]> => {
    return stream.pipe(
      topKFunction(
        (a: ValueType, b: ValueType) =>
          comparator(valueExtractor(a), valueExtractor(b)),
        {
          limit,
          offset,
          setSizeCallback,
          setWindowFn,
        },
      ),
      consolidate(),
    )
  }
}

/**
 * Orders the elements and limits the number of results, with optional offset and