Keyed DB

A light-weight Node.js/TypeScript library to manage a sorted & indexed collection with pagination support.
All done using binary search.

Originally based on Swift code written for Queenfisher.

Install

``bash
npm i @thehackingguard/keyed-db
`

Running Tests

`bash
npm test
`

Quick Start

CommonJS
`js
const KeyedDB = require('@thehackingguard/keyed-db')
`

ESM/TypeScript
`ts
import KeyedDB from '@thehackingguard/keyed-db'
`

Constructor

`ts
const db = new KeyedDB(
{ key: t => t.uniqueNumberKeyProperty },
t => t.optionalUniqueIDProperty
)
`

With a custom comparison:

`ts
const db = new KeyedDB(
{
key: t => t.someProperty,
compare: (t1, t2) => t1 < t2 ? -1 : t1 > t2 ? 1 : 0
},
t => t.optionalUniqueIDProperty
)
`

Functions

`ts
db.insert(value) // insert value in DB
db.upsert(value) // upserts value
db.insertIfAbsent(value) // only inserts if not already present in DB
db.delete(value) // delete value
db.deleteById(id) // delete value by referencing the ID
db.updateKey(value, updater) // update the key of a value & re-place it
db.paginated(cursor, limit) // get X results after the given cursor (null for the first page)
`

Usage Example

`ts
import KeyedDB from '@thehackingguard/keyed-db'

type Chat = {
timestamp: Date
chatID: string
}

const db = new KeyedDB(
{ key: value => value.timestamp.getTime() * -1 },
value => value.chatID
)

for (let i = 0; i < 1000; i++) {
db.insert({
timestamp: new Date(new Date().getTime() - Math.random() * 10000),
chatID: person ${i}
})
}

console.log(db.all())
console.log(db.paginated(null, 20))
console.log(db.paginated(null, 20, null, 'before'))
console.log(db.paginated(null, 20, chat => chat.chatID.includes('something')))

const someDate = new Date().getTime()
const cursorPaginated = db.paginated(someDate, 20)
console.log(cursorPaginated)

db.delete(cursorPaginated[0])
db.updateKey(cursorPaginated[1], value => (value.timestamp = new Date()))
``

Time Complexity

| Operation | Time Complexity |
|----------------|-----------------|
| db.insert() | O(logN) |
| db.delete() | O(logN) |
| db.get() | O(1) |
| db.updateKey() | O(logN) |

License

GPL-3.0.

Attribution

Published as @thehackingguard/keyed-db. Derived from original keyed-db work by adiwajshing (GPL licensed).
All original notices and GPL-3.0 terms are preserved.