enzyme / collection

     *

     * @return \Enzyme\Collection\Collection

     */

    public function map(Closure $fn)

    {

        $results = [];

        foreach ($this->items as $key => $value) {

            $results[] = $fn($value, $key);

        }

        return new static($results);

    }

    /**

     * Pluck out all values in this collection which have the specified key.

     *

     * @return \Enzyme\Collection\Collection

     */

    public function filter(Closure $fn)

    {

        $results = [];

        foreach ($this->items as $key => $value) {

            if (true === $fn($value, $key)) {

                $results[$key] = $value;

            }

        }

        // Pushing this new array will normalize numeric keys if they exist.

        // After filtering, they may not start at zero and sequentially

        // go upwards, which is generally not expected.

        return (new static())->pushArray($results);

    }

    /**

     * Sort the collection using the provided callback function. Same expected