random-access-pool.ts

class RandomAccessPool<T> {
  readonly items: readonly T[]
  protected pool: T[] = []

  constructor(items: T[]) {
    this.items = items
  }

  get() {
    if (!this.pool.length) {
      this.pool = [...this.items]
    }

    const index = Math.floor(Math.random() * this.pool.length)
    return this.pool.splice(index, 1)[0]
  }
}

const rap = new RandomAccessPool([1,2,3])

for (const it of [...Array(25)]) {
  console.log(rap.get())
}