How to check if KEY exists or alternatively check if VALUE exists in all keys

[unnaturalistic]

how to check if a key exists or alternatively if a value exists in the database
i am using nodejs and making an express app

[vweevers]

See Level/community#106, which contains several ways to do it today, and a proposal for doing it with a new API that would have optimal performance.

As for checking whether a value exists, that doesn't fit in the key-centric design of level (or any key-value database). You would have to create an index so that you can lookup values (as keys).

[unnaturalistic]

thank you!