Method reduce

packages/core/src/entity/Collection.ts:813–822

* Maps the collection items based on your provided mapper function to a single object.

(cb: (obj: R, item: T, index: number) => R, initial = {} as R)

   * Maps the collection items based on your provided mapper function to a single object.
   */
  reduce<R>(cb: (obj: R, item: T, index: number) => R, initial = {} as R): R {
    this.checkInitialized();
    let index = 0;

    for (const item of this.#items) {
      initial = cb(initial, item, index++);
    }

    return initial;
  }

  /**
   * Maps the collection items to a dictionary, indexed by the key you specify.