DataStructures/Queues.js at main · Egor228322/DataStructures · GitHub

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class Node {
    constructor(value) {
        this.value = value;
        this.next = null;
    }
}

class Queue {
    constructor() {
        this.first = null;
        this.last = null;
        this.length = 0
    }

    peek() {
        return this.first;
    }

    enqueue(value) {
        const newNode = new Node(value);
        if (this.length == 0) {
            this.first = newNode;
            this.last = newNode;
        } else {
            this.last.next = newNode;
            this.last = newNode;
        }
        this.length++;
        return this;

    }

    dequeue() {

        if(!this.first) {
            return null;
        }
        if(this.first === this.last) {
            this.last = null;
        }
        this.first = this.first.next;
        this.length--;
        return this;
    }

}

const myQueue = new Queue();
myQueue.enqueue(1);
myQueue.enqueue(2);
myQueue.dequeue();
console.log(myQueue.enqueue(3));
console.log(myQueue);