Method nextLowerPair

packages/db/src/utils/btree.ts:271–277

Returns the next pair whose key is smaller than the specified key (or undefined if there is none). * If key === undefined, this function returns the highest pair. * @param key The key to search for. * @param reusedArray Optional array used repeatedly to store key-value pairs, to *

(key: K | undefined, reusedArray?: [K, V])

   *        avoid creating a new array each time you call this method.
   */
  nextLowerPair(key: K | undefined, reusedArray?: [K, V]): [K, V] | undefined {
    reusedArray = reusedArray || ([] as unknown as [K, V])
    if (key === undefined) {
      return this._root.maxPair(reusedArray)
    }
    return this._root.getPairOrNextLower(key, this._compare, false, reusedArray)
  }

  /** Returns the next key smaller than the specified key, or undefined if there is none.
   *  Also, nextLowerKey(undefined) returns the highest key.