The IDBKeyRange interface of the IndexedDB API represents a continuous interval over some data type that is used for keys.
IDBKeyRange
MDN Reference
The lower read-only property of the IDBKeyRange interface returns the lower bound of the key range.
lower
The lowerOpen read-only property of the IDBKeyRange interface returns a boolean indicating whether the lower-bound value is included in the key range.
lowerOpen
The upper read-only property of the IDBKeyRange interface returns the upper bound of the key range.
upper
The upperOpen read-only property of the IDBKeyRange interface returns a boolean indicating whether the upper-bound value is included in the key range.
upperOpen
The includes() method of the IDBKeyRange interface returns a boolean indicating whether a specified key is inside the key range.
includes()