mongita VS NeDB

It's a good question and to be accurate, depending on the benchmark, Mongita is about the same speed at SQLite to several-times slower.

There is less happening algorithmically than you would think. Where the tricky slow bits do exist, they have largely fallen into the happy-path of fast data structures in the Python language/stdlib. I also use sortedcontainers for indexes which helped quite a bit (http://www.grantjenks.com/docs/sortedcontainers/).

If you're curious, the benchmark code is in the repo: https://github.com/scottrogowski/mongita/blob/master/benchma...

What I'd do to get the best understanding of how NeDB works is to dive into the docs here. The primary things to keep in mind are that there can be other non-JSON data in those files, and that all of the document data is appended and periodically compacted, which means you'll often have an arbitrary number of duplicates and versions within the same file.

I've used https://github.com/louischatriot/nedb before but it may not meet your needs.

NeDB compatible with MongoDB

Also, there is a javascript solution called nedb: https://github.com/louischatriot/nedb, which does largely the same thing

There is similar project in Javascript called NeDB

Nicely done!

I like the small codebase with no dependencies - I imagine it's easy to start using. Also appreciate the extensive query interface and documentation.

It reminds me of NeDB in Node.js world, which has proven its worth to me on several occasions when I needed a simple JSON-based database with mostly read operations (which are served from memory), running for literally years with no issue at all.

https://github.com/louischatriot/nedb

nedb is the package you are searching for. Just JS, same syntax as MongoDB, runs in RAM and can persist data on disk