Real Queue JS

This package represents fifo Queue data structure. Provides basic queue functionality. The reason of this library to exists is poor js array shift method performance. If you need to remove a lot of items from the top of the array, for best experience use Queue instead. You can find performance comparison in the performance section.

Requirements

• NodeJS: 13.2+
• NPM: 6.13+

Install

npm install real-queue

Docs

Provides default fifo queue functionality.

constructor()

Creates an Queue instance. Receives no parameters.

push(data: any): void

Pushes data to the end of the queue.

pop(): void

Removes next item from the queue

Throws an error if there are no items in the queue.

front(): any

Returns next (first) item in the queue.

Throws an error if there are no items in the queue.

back(): any

Returns last item in the queue

Throws an error if there are no items in the queue.

size(): number

Returns number of elements in the queue

empty(): boolean

Returns true if the queue is empty and false otherwise.

Examples

const q = new Queue();
for(let i=0;i<10;i++) {
    q.push(i);
}
while(!q.empty()){
    console.log(q.front()); // 0 1 2...
    q.pop();
}

Performance

Running next script

import {Queue} from 'real-queue'

// Time for push to js array
let t = Date.now();
const arr = [];
for(let i=0;i<100000;i++){
    arr.push(i);
}
console.log('Array push', Date.now()-t);

// Time for shift from js array
t = Date.now();
for(let i=0;i<100000;i++){
    arr.shift();
}
console.log('Array shift', Date.now()-t);

// Time for push to Queue
t = Date.now();
const q = new Queue();
for(let i=0;i<100000;i++){
    q.push(i);
}
console.log('Queue push', Date.now()-t);

// Time for pop from Queue
t = Date.now();
for(let i=0;i<100000;i++){
    q.pop();
}
console.log('Queue pop', Date.now()-t);

gives the next results:

Array push 8
Array shift 853
Queue push 16
Queue pop 6

It takes almost a second for shifting 100`000 items from array, and just a 6ms to remove items from Queue!

License

MIT

Have fun!