compact-db

A lightweight embedded database inspired from leveldb but operate in sync mode.


Why compact-db?

To free your code from callback hell and async await.

What is it not good for?

If your application need to serve for multiple users / concurrent tasks, and you favour average "concurrent performance" over "raw throughput", you may better adopt leveldb or other asynchronous database.

Features

- [x] sync mode operation
- [x] fully tested (with jest)
- [x] efficient disk space consumption (with auto compaction)
- [x] support atomic, batched operations
- [x] fault tolerant to program crash
- [x] simple interface (similar to Map)
- [x] small code base (~250 loc)

Usage

Import and create database instance:
``typescript
import { createDB } from 'compact-db'

let db = createDB({ path: 'data' })
`

Database options and supported methods (from dist/db.d.ts):
`typescript
export type Key = string | number

export declare function createDB(options: {
path: string

// default 8 MB
batch_read_size?: number

// default 2 (compact will occur when the file size of LOG file is twice as DATA file)
compact_ratio?: number
}): {
get: (key: Key) => T | undefined;
set: (key: Key, value: any) => void;
del: (key: Key) => void;
clear: () => void;
batch: (batch: Batch) => void;
keys: () => string[];
entries: () => any[][];
values: () => any[];
};
`

Type signature of batch operations:
`typescript
export declare type Batch = Op[];
export declare type Op = {
type: 'del';
key: Key;
} | {
type: 'set';
key: Key;
value: any;
} | {
type: 'clear';
};
``

Details refer to the test spec

License

This project is licensed with BSD-2-Clause

This is free, libre, and open-source software. It comes down to four essential freedoms [[ref]](https://seirdy.one/2021/01/27/whatsapp-and-the-domestication-of-users.html#fnref:2):

- The freedom to run the program as you wish, for any purpose
- The freedom to study how the program works, and change it so it does your computing as you wish
- The freedom to redistribute copies so you can help others
- The freedom to distribute copies of your modified versions to others