fundamentals

Small JavaScript data-structure utilities (ESM).

Currently included:

- Queue: FIFO queue
- PriorityQueue: queue ordered by numeric priority (ascending by default)

Installation

``bash
npm i js-fundamentals
`

Usage

This package is ESM-only ("type": "module").

`js
import { Queue, PriorityQueue } from "js-fundamentals";
`

$3

`js
import { Queue } from "js-fundamentals";

const q = new Queue();
q.enqueue("a");
q.enqueue("b");

q.peek(); // "a"
q.dequeue(); // "a"
q.size(); // 1
q.toArray(); // ["b"]
`

$3

PriorityQueue stores (item, priority) pairs internally and always dequeues the next item based on priority.

By default it is ascending (lower numbers come out first). Pass { descending: true } to the constructor for descending order.

`js
import { PriorityQueue } from "js-fundamentals";

const pq = new PriorityQueue(); // ascending
pq.enqueue("low", 10);
pq.enqueue("high", 1);

pq.dequeue(); // "high"
pq.toArray(); // ["low"]
`

Descending order:

`js
const pq = new PriorityQueue({ descending: true }); // descending
pq.enqueue("low", 1);
pq.enqueue("high", 10);

pq.dequeue(); // "high"
`

API

$3

- enqueue(item): void
- dequeue(): any | undefined (returns undefined if empty)
- peek(): any | undefined (returns undefined if empty)
- isEmpty(): boolean
- size(): number
- toArray(): any[] (returns the internal backing array)

$3

Extends Queue.

- options.descending?: boolean (default: false)
- enqueue(item, priority): void (priority should be a number)
- dequeue(): any | undefined (returns undefined if empty)
- peek(): any | undefined (returns undefined if empty)
- isEmpty(): boolean
- size(): number
- toArray(): any[] (returns only items, not priorities)
- changePriority(item, newPriority): void
- Finds an existing item and updates its priority, then re-sorts the queue.
- Matching rules:
- Uses strict equality (===) for non-objects
- For non-null objects, falls back to JSON.stringify comparison
- Throws Error("Item not found") if no match is found.

Development

`bash
npm test
npm run lint
npm run format
``