| 1 | // Copyright Jerome Benoit. 2021-2023. All Rights Reserved. |
| 2 | |
| 3 | /** |
| 4 | * Queue |
| 5 | * |
| 6 | * @typeParam T - Type of queue items. |
| 7 | */ |
| 8 | export class Queue<T> { |
| 9 | private items: Record<number, T> |
| 10 | private head: number |
| 11 | private tail: number |
| 12 | |
| 13 | public constructor () { |
| 14 | this.items = {} |
| 15 | this.head = 0 |
| 16 | this.tail = 0 |
| 17 | } |
| 18 | |
| 19 | /** |
| 20 | * Get the size of the queue. |
| 21 | * |
| 22 | * @returns The size of the queue. |
| 23 | * @readonly |
| 24 | */ |
| 25 | public get size (): number { |
| 26 | return this.tail - this.head |
| 27 | } |
| 28 | |
| 29 | /** |
| 30 | * Enqueue an item. |
| 31 | * |
| 32 | * @param item - Item to enqueue. |
| 33 | * @returns The new size of the queue. |
| 34 | */ |
| 35 | public enqueue (item: T): number { |
| 36 | this.items[this.tail] = item |
| 37 | this.tail++ |
| 38 | return this.size |
| 39 | } |
| 40 | |
| 41 | /** |
| 42 | * Dequeue an item. |
| 43 | * |
| 44 | * @returns The dequeued item or `undefined` if the queue is empty. |
| 45 | */ |
| 46 | public dequeue (): T | undefined { |
| 47 | if (this.size <= 0) return undefined |
| 48 | const item = this.items[this.head] |
| 49 | // eslint-disable-next-line @typescript-eslint/no-dynamic-delete |
| 50 | delete this.items[this.head] |
| 51 | this.head++ |
| 52 | if (this.head === this.tail) { |
| 53 | this.head = 0 |
| 54 | this.tail = 0 |
| 55 | } |
| 56 | return item |
| 57 | } |
| 58 | } |