A simple Pool class I used for Trans Neuronica

Pool.ts

export class Pool<T>
{
	private readonly _pool: T[];
	private readonly _construct: () => T;
	private readonly _autoHydrateSize: number;
	private _indexInPool: number;

	constructor(initialCapacity: number, construct: () => T, autoHydrateSize: number = 1)
	{
		this._pool = [];
		this._indexInPool = 0;
		this._autoHydrateSize = autoHydrateSize;
		this._construct = construct;

		this.hydrate(initialCapacity);
	}

	public getOne()
	{
		if (this._indexInPool === 0) {
			this.hydrate(this._autoHydrateSize);
		}

		return this._pool[--this._indexInPool];
	}

	public hydrate(instancesToAdd: number)
	{
		if (instancesToAdd < 0) {
			throw new Error("`instancesToAdd` cannot be less than 0");
		}

		while (instancesToAdd-- > 0) {
			this._pool[this._indexInPool++] = this._construct();
		}
	}

	public release(instance: T)
	{
		this._pool[this._indexInPool++] = instance;
	}
}