| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | * |
| 7 | * Shared logic for Fragment Ref operations for DOM and Fabric configs |
| 8 | * |
| 9 | * @flow |
| 10 | */ |
| 11 | |
| 12 | import type {Fiber} from 'react-reconciler/src/ReactInternalTypes'; |
| 13 | |
| 14 | import {getFragmentInstanceOrTextInstanceSiblings} from 'react-reconciler/src/ReactFiberTreeReflection'; |
| 15 | |
| 16 | export function compareDocumentPositionForEmptyFragment<TPublicInstance>( |
| 17 | fragmentFiber: Fiber, |
| 18 | parentHostInstance: TPublicInstance, |
| 19 | otherNode: TPublicInstance, |
| 20 | getPublicInstance: (fiber: Fiber) => TPublicInstance, |
| 21 | ): number { |
| 22 | let result; |
| 23 | // If the fragment has no children, we can use the parent and |
| 24 | // siblings to determine a position. |
| 25 | // $FlowFixMe[incompatible-use] Fabric PublicInstance is opaque |
| 26 | // $FlowFixMe[prop-missing] |
| 27 | const parentResult = parentHostInstance.compareDocumentPosition(otherNode); |
| 28 | result = parentResult; |
| 29 | if (parentHostInstance === otherNode) { |
| 30 | result = Node.DOCUMENT_POSITION_CONTAINS; |
| 31 | } else { |
| 32 | if (parentResult & Node.DOCUMENT_POSITION_CONTAINED_BY) { |
| 33 | // otherNode is one of the fragment's siblings. Use the next |
| 34 | // host sibling (via the parent tree, not fiber.sibling) to |
| 35 | // determine if its preceding or following. |
| 36 | const [, nextSiblingFiber] = |
| 37 | getFragmentInstanceOrTextInstanceSiblings(fragmentFiber); |
| 38 | if (nextSiblingFiber === null) { |
| 39 | result = Node.DOCUMENT_POSITION_PRECEDING; |
| 40 | } else { |
| 41 | const nextSiblingInstance = getPublicInstance(nextSiblingFiber); |
| 42 | const nextSiblingResult = |
| 43 | // $FlowFixMe[incompatible-use] Fabric PublicInstance is opaque |
| 44 | // $FlowFixMe[prop-missing] |
| 45 | nextSiblingInstance.compareDocumentPosition(otherNode); |
| 46 | if ( |
| 47 | nextSiblingResult === 0 || |
| 48 | nextSiblingResult & Node.DOCUMENT_POSITION_FOLLOWING |
| 49 | ) { |
| 50 | result = Node.DOCUMENT_POSITION_FOLLOWING; |
| 51 | } else { |
| 52 | result = Node.DOCUMENT_POSITION_PRECEDING; |
| 53 | } |
| 54 | } |
| 55 | } |
| 56 | } |
| 57 | |
| 58 | result |= Node.DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC; |
| 59 | return result; |
| 60 | } |