Method map

packages/db/src/collection/index.ts:557–570

* Create a new array with the results of calling a function for each entry in the collection

(
    callbackfn: (
      value: WithVirtualProps<TOutput, TKey>,
      key: TKey,
      index: number,
    ) => U,
  )

   * Create a new array with the results of calling a function for each entry in the collection
   */
  public map<U>(
    callbackfn: (
      value: WithVirtualProps<TOutput, TKey>,
      key: TKey,
      index: number,
    ) => U,
  ): Array<U> {
    const result: Array<U> = []
    let index = 0
    for (const [key, value] of this.entries()) {
      result.push(callbackfn(value, key, index++))
    }
    return result
  }

  public getKeyFromItem(item: TOutput): TKey {
    return this.config.getKey(item)