@nent/core/dist/collection/services/common/mutex.js

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/*!
 * NENT 2022
 */
/* It's a mutex that allows you to dispatch a function that will be executed in order */
export class Mutex {
  constructor() {
    this.mutex = Promise.resolve();
  }
  /**
   * "The mutex is a promise that resolves to a promise that resolves to a function that unlocks the
   * mutex."
   *
   * The mutex is a promise that resolves to a promise that resolves to a function that unlocks the
   * mutex
   * @returns A promise that resolves to a function that unlocks the mutex.
   */
  lock() {
    let begin = _unlock => { };
    this.mutex = this.mutex.then(() => {
      return new Promise(begin);
    });
    return new Promise(res => {
      begin = res;
    });
  }
  /**
   * It takes a function as an argument, and returns a promise that resolves to the return value of
   * that function
   * @param {(() => T) | (() => PromiseLike<T>)} fn - (() => T) | (() => PromiseLike<T>)
   * @returns A promise that resolves to the result of the function passed in.
   */
  async dispatch(fn) {
    const unlock = await this.lock();
    try {
      return await Promise.resolve(fn());
    }
    finally {
      unlock();
    }
  }
}