Simplest JavaScript Queue (best performance) single linked list.

Queue.js

class Queue
{
    constructor()
    {
        this.count = 0;
        this.tail = this.root = {
            next:null
        };
    }

    enqueue(value) {
        const newTail = { value: value }
        this.tail.next = newTail;
        this.tail = newTail;
        this.count++;
    }

    dequeue() {
        const n = this.root.next;
        if(!n) return undefined;
        this.root.next = n.next;
        this.count--;
        if(n.next) n.next = null;
        else this.tail = this.root;
        return n.value;
    }
}