Rs\Json\Patch\Operations\Add::perform PHP Метод

    public function perform($targetDocument)
    {
        $pointer = new Pointer($targetDocument);
        $rootGet = array();
        $value = $this->getValue();
        try {
            $get = $pointer->get($this->getPath());
        } catch (NonexistentValueReferencedException $e) {
            $get = null;
        }
        $pointerParts = $this->getPointerParts();
        $rootPointer = $pointerParts[0];
        if (count($pointerParts) >= 2) {
            try {
                $rootGet = $pointer->get(Pointer::POINTER_CHAR . implode('/', array_slice($pointerParts, 0, -1)));
            } catch (NonexistentValueReferencedException $e) {
                return $targetDocument;
            }
        }
        $targetDocument = json_decode($targetDocument);
        $lastPointerPart = $pointerParts[count($pointerParts) - 1];
        $replacementValue = $this->getReplacementValue();
        if ($get === null && $lastPointerPart !== Pointer::LAST_ARRAY_ELEMENT_CHAR) {
            if (ctype_digit($lastPointerPart) && $lastPointerPart > count($rootGet)) {
                if ($rootPointer == $lastPointerPart && is_array($targetDocument)) {
                    if ((int) $lastPointerPart <= count($targetDocument) + 1) {
                        array_splice($targetDocument, $lastPointerPart, 0, $replacementValue);
                    }
                }
                return json_encode($targetDocument, JSON_UNESCAPED_UNICODE);
            }
            if (count($pointerParts) === 1) {
                if (is_array($targetDocument)) {
                    $targetDocument[$pointerParts[0]] = $value;
                } else {
                    $targetDocument->{$pointerParts[0]} = $value;
                }
            } elseif (count($pointerParts) > 1) {
                $augmentedDocument =& $targetDocument;
                foreach ($pointerParts as $pointerPart) {
                    if (is_array($augmentedDocument)) {
                        $augmentedDocument =& $augmentedDocument[$pointerPart];
                    } else {
                        $augmentedDocument =& $augmentedDocument->{$pointerPart};
                    }
                }
                $augmentedDocument = $value;
            }
        } else {
            $additionIndex = array_pop($pointerParts);
            $arrayEntryPath = '/' . implode('/', $pointerParts);
            try {
                $targetArray = $pointer->get($arrayEntryPath);
            } catch (NonexistentValueReferencedException $e) {
                $targetArray = null;
            }
            if (is_array($targetArray)) {
                if ($lastPointerPart === Pointer::LAST_ARRAY_ELEMENT_CHAR) {
                    $targetArray[] = $value;
                } else {
                    if (is_numeric($additionIndex)) {
                        array_splice($targetArray, $additionIndex, 0, $replacementValue);
                    } else {
                        $targetArray[$additionIndex] = $value;
                    }
                }
            }
            if (is_object($targetArray)) {
                $targetArray->{$additionIndex} = $value;
            }
            if (is_array($targetArray) || is_object($targetArray)) {
                $augmentedDocument =& $targetDocument;
                foreach ($pointerParts as $pointerPart) {
                    if (is_array($augmentedDocument)) {
                        $augmentedDocument =& $augmentedDocument[$pointerPart];
                    } else {
                        $augmentedDocument =& $augmentedDocument->{$pointerPart};
                    }
                }
                $augmentedDocument = $targetArray;
            }
            if ($targetArray === null) {
                if (is_numeric($additionIndex) && count($targetDocument) > 0) {
                    array_splice($targetDocument, $additionIndex, 0, $replacementValue);
                } else {
                    $targetDocument->{$additionIndex} = $value;
                }
            }
        }
        return json_encode($targetDocument, JSON_UNESCAPED_UNICODE);
    }

 /**
  * @param  string $targetDocument
  *
  * @throws \Rs\Json\Patch\InvalidOperationException
  * @throws \Rs\Json\Pointer\InvalidJsonException
  * @throws \Rs\Json\Pointer\InvalidPointerException
  * @throws \Rs\Json\Pointer\NonWalkableJsonException
  * @throws \RuntimeException
  * @return string
  */
 public function perform($targetDocument)
 {
     $pointer = new Pointer($targetDocument);
     try {
         $get = $pointer->get($this->getFrom());
     } catch (NonexistentValueReferencedException $e) {
         return $targetDocument;
     }
     if ($this->getFrom() === $this->getPath()) {
         return $targetDocument;
     }
     $operation = new \stdClass();
     $operation->path = $this->getPath();
     $operation->value = $get;
     $add = new Add($operation);
     return $add->perform($targetDocument);
 }