Tim van der Lippe | c7b05fe | 2021-02-12 15:43:31 +0000 | [diff] [blame^] | 1 | class Node { |
| 2 | /// value; |
| 3 | /// next; |
| 4 | |
| 5 | constructor(value) { |
| 6 | this.value = value; |
| 7 | |
| 8 | // TODO: Remove this when targeting Node.js 12. |
| 9 | this.next = undefined; |
| 10 | } |
| 11 | } |
| 12 | |
| 13 | class Queue { |
| 14 | // TODO: Use private class fields when targeting Node.js 12. |
| 15 | // #_head; |
| 16 | // #_tail; |
| 17 | // #_size; |
| 18 | |
| 19 | constructor() { |
| 20 | this.clear(); |
| 21 | } |
| 22 | |
| 23 | enqueue(value) { |
| 24 | const node = new Node(value); |
| 25 | |
| 26 | if (this._head) { |
| 27 | this._tail.next = node; |
| 28 | this._tail = node; |
| 29 | } else { |
| 30 | this._head = node; |
| 31 | this._tail = node; |
| 32 | } |
| 33 | |
| 34 | this._size++; |
| 35 | } |
| 36 | |
| 37 | dequeue() { |
| 38 | const current = this._head; |
| 39 | if (!current) { |
| 40 | return; |
| 41 | } |
| 42 | |
| 43 | this._head = this._head.next; |
| 44 | this._size--; |
| 45 | return current.value; |
| 46 | } |
| 47 | |
| 48 | clear() { |
| 49 | this._head = undefined; |
| 50 | this._tail = undefined; |
| 51 | this._size = 0; |
| 52 | } |
| 53 | |
| 54 | get size() { |
| 55 | return this._size; |
| 56 | } |
| 57 | |
| 58 | * [Symbol.iterator]() { |
| 59 | let current = this._head; |
| 60 | |
| 61 | while (current) { |
| 62 | yield current.value; |
| 63 | current = current.next; |
| 64 | } |
| 65 | } |
| 66 | } |
| 67 | |
| 68 | module.exports = Queue; |