levelup
A wrapper for abstract-leveldown compliant stores, for Node.js
... by keys. This makes the streaming interface of levelup - which exposes LevelDB iterators as Readable Streams, a very powerful query mechanism. The most common store is leveldown which provides a pure C++ binding to LevelDB. Many alternative stores are available such as level.js in the browser or memdown for an in-memory store. They typically support strings and Buffers for both keys and values. For a richer set of data types you can wrap the store with encoding-down.