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import { InvalidMaxError } from "./errors.ts";
/** * A class that generates an index number. */export class Indexer {  #max: number;  #val: number;
  /**   * Constructs a new Indexer.   *   * @param max The maximum value of the index.   * @throws {InvalidMaxError} If the max is not an integer greater than 1.   */  constructor(max?: number) {    if (max != null && (!Number.isInteger(max) || max < 2)) {      throw new InvalidMaxError(        `The max must be an integer greater than 1 but ${max} has given`,        max,      );    }    this.#max = max ?? Number.MAX_SAFE_INTEGER;    this.#val = -1;  }
  /**   * Returns the next index number and increments the index number.   *   * It starts from 0 and increments the index number by 1 each time it is called.   * It resets the index number and returns 0 if the index number is greater than or equal to the max.   */  next(): number {    if (this.#val >= this.#max) {      this.#val = -1;    }    this.#val += 1;    return this.#val;  }}