prsm/packages/duplex/src/server/ids.ts

export class IdManager {
  ids: Array<true | false> = [];
  index: number = 0;
  maxIndex: number;

  constructor(maxIndex: number = 2 ** 16 - 1) {
    this.maxIndex = maxIndex;
  }

  release(id: number) {
    if (id < 0 || id > this.maxIndex) {
      throw new TypeError(
        `ID must be between 0 and ${this.maxIndex}. Got ${id}.`,
      );
    }
    this.ids[id] = false;
  }

  reserve(): number {
    const startIndex = this.index;

    while (true) {
      const i = this.index;

      if (!this.ids[i]) {
        this.ids[i] = true;

        return i;
      }

      if (this.index >= this.maxIndex) {
        this.index = 0;
      } else {
        this.index++;
      }

      if (this.index === startIndex) {
        throw new Error(
          `All IDs are reserved. Make sure to release IDs when they are no longer used.`,
        );
      }
    }
  }
}