def get_diff()

in warehouse/src/on_order_events/main.py [0:0]

• 17 lines of code
• 6 McCabe index (conditional complexity)

def get_diff(old_products: List[dict], new_products: List[dict]) -> Dict[str, dict]:
    """
    Returns the difference between two lists of products

    The difference contains three possible keys: 'created', 'deleted' or 'modified'.
    """

    # Transform lists into dict
    old = {p["productId"]: p for p in old_products}
    new = {p["productId"]: p for p in new_products}

    diff = {
        "created": [],
        "deleted": [],
        "modified": []
    }

    for product_id, product in new.items():
        if product_id not in old:
            diff["created"].append(product)
            continue

        if product != old[product_id]:
            # As DynamoDB put_item operations overwrite the whole item, we
            # don't need to save the old item.
            diff["modified"].append(product)

        # Remove the item from old
        del old[product_id]

    # Since we delete values from 'old' as we encounter them, only values that
    # are in 'old' but not in 'new' are left. Therefore, these were deleted
    # from the original order.
    diff["deleted"] = list(old.values())

    return diff