/*
How it works:
`this.#head` is an instance of `Node` which keeps track of its current value and nests another instance of `Node` that keeps the value that comes after it. When a value is provided to `.enqueue()`, the code needs to iterate through `this.#head`, going deeper and deeper to find the last value. However, iterating through every single item is slow. This problem is solved by saving a reference to the last value as `this.#tail` so that it can reference it to add a new value.
*/
class Node {
value;
next;
constructor(value) {
this.value = value;
}
}
export default class Queue {
#head;
#tail;
#size;
constructor() {
this.clear();
}
enqueue(value) {
const node = new Node(value);
if (this.#head) {
this.#tail.next = node;
this.#tail = node;
} else {
this.#head = node;
this.#tail = node;
}
this.#size++;
}
dequeue() {
const current = this.#head;
if (!current) {
return;
}
this.#head = this.#head.next;
this.#size--;
return current.value;
}
clear() {
this.#head = undefined;
this.#tail = undefined;
this.#size = 0;
}
get size() {
return this.#size;
}
* [Symbol.iterator]() {
let current = this.#head;
while (current) {
yield current.value;
current = current.next;
}
}
}
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