Zalas\Collection\LazyCollection

Complexity

Total Complexity

12

Size/Duplication

Total Lines	60
Duplicated Lines	0 %

Test Coverage

Coverage

100%

Importance

Changes	2
Bugs	0	Features	0

7 Methods

Rating	Name	Duplication	Size	Complexity
A	__construct()	0	3	1
A	filter()	0	6	3
A	getIterator()	0	3	1
A	merge()	0	8	3
A	reduce()	0	3	1
A	createFromClosure()	0	3	1
A	map()	0	5	2

<?php declare(strict_types=1);

namespace Zalas\Collection;

use Closure;
use Traversable;

final class LazyCollection implements Collection
{
    private $elements;

    public function __construct(Traversable $elements)
    {
        $this->elements = $elements;
    }

    public function getIterator(): Traversable
    {
        yield from $this->elements;
    }

    public function merge(Collection $other): Collection
    {
        return self::createFromClosure(function () use ($other) {
            foreach ($this as $e) {
                yield $e;
            }
            foreach ($other as $e) {
                yield $e;
            }
        });
    }

    public function filter(callable $f): Collection
    {
        return self::createFromClosure(function () use ($f) {
            foreach ($this as $e) {
                if ($f($e)) {
                    yield $e;
                }
            }
        });
    }

    public function map(callable $f): Collection
    {
        return self::createFromClosure(function () use ($f) {
            foreach ($this as $e) {
                yield $f($e);
            }
        });
    }

    /**
     * @param mixed $initial
     * @param callable $f
     *
     * @return mixed
     */
    public function reduce($initial, callable $f)
    {
        return \array_reduce(\iterator_to_array($this), $f, $initial);
    }

    private static function createFromClosure(Closure $f): Collection
    {
        return new self($f());
    }
}