{"body":"[Fiber] Use `T | null` instead of `?T` types","parents":["7958c1d77d603dce54355a3005e3afdb9bc35ace","350d736361f5a86d94960cfd230ff7f77a21785b"],"patch":"diff --git a\/src\/renderers\/shared\/fiber\/ReactChildFiber.js b\/src\/renderers\/shared\/fiber\/ReactChildFiber.js\nindex ceb7dc345b..79f80c9e40 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactChildFiber.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactChildFiber.js\n@@ -73,9 +73,9 @@ const {\n Deletion,\n } = ReactTypeOfSideEffect;\n \n-function coerceRef(current: ?Fiber, element: ReactElement) {\n+function coerceRef(current: Fiber | null, element: ReactElement) {\n let mixedRef = element.ref;\n- if (mixedRef != null && typeof mixedRef !== 'function') {\n+ if (mixedRef !== null && typeof mixedRef !== 'function') {\n if (element._owner) {\n const owner : ?(Fiber | ReactInstance) = (element._owner : any);\n let inst;\n@@ -97,7 +97,7 @@ function coerceRef(current: ?Fiber, element: ReactElement) {\n );\n const stringRef = String(mixedRef);\n \/\/ Check if previous string ref matches new string ref\n- if (current && current.ref && current.ref._stringRef === stringRef) {\n+ if (current !== null && current.ref !== null && current.ref._stringRef === stringRef) {\n return current.ref;\n }\n const ref = function(value) {\n@@ -161,14 +161,14 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \/\/ When we're reconciling in place we have a work in progress copy. We\n \/\/ actually want the current copy. If there is no current copy, then we\n \/\/ don't need to track deletion side-effects.\n- if (!childToDelete.alternate) {\n+ if (childToDelete.alternate === null) {\n return;\n }\n childToDelete = childToDelete.alternate;\n }\n \/\/ Deletions are added in reversed order so we add it to the front.\n const last = returnFiber.progressedLastDeletion;\n- if (last) {\n+ if (last !== null) {\n last.nextEffect = childToDelete;\n returnFiber.progressedLastDeletion = childToDelete;\n } else {\n@@ -182,7 +182,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function deleteRemainingChildren(\n returnFiber : Fiber,\n- currentFirstChild : ?Fiber\n+ currentFirstChild : Fiber | null\n ) : null {\n if (!shouldTrackSideEffects) {\n \/\/ Noop.\n@@ -192,7 +192,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \/\/ TODO: For the shouldClone case, this could be micro-optimized a bit by\n \/\/ assuming that after the first child we've already added everything.\n let childToDelete = currentFirstChild;\n- while (childToDelete) {\n+ while (childToDelete !== null) {\n deleteChild(returnFiber, childToDelete);\n childToDelete = childToDelete.sibling;\n }\n@@ -209,7 +209,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n const existingChildren : Map = new Map();\n \n let existingChild = currentFirstChild;\n- while (existingChild) {\n+ while (existingChild !== null) {\n if (existingChild.key !== null) {\n existingChildren.set(existingChild.key, existingChild);\n } else {\n@@ -247,7 +247,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n return lastPlacedIndex;\n }\n const current = newFiber.alternate;\n- if (current) {\n+ if (current !== null) {\n const oldIndex = current.index;\n if (oldIndex < lastPlacedIndex) {\n \/\/ This is a move.\n@@ -267,7 +267,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n function placeSingleChild(newFiber : Fiber) : Fiber {\n \/\/ This is simpler for the single child case. We only need to do a\n \/\/ placement for inserting new children.\n- if (shouldTrackSideEffects && !newFiber.alternate) {\n+ if (shouldTrackSideEffects && newFiber.alternate === null) {\n newFiber.effectTag = Placement;\n }\n return newFiber;\n@@ -275,11 +275,11 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function updateTextNode(\n returnFiber : Fiber,\n- current : ?Fiber,\n+ current : Fiber | null,\n textContent : string,\n priority : PriorityLevel\n ) {\n- if (current == null || current.tag !== HostText) {\n+ if (current === null || current.tag !== HostText) {\n \/\/ Insert\n const created = createFiberFromText(textContent, priority);\n created.return = returnFiber;\n@@ -295,11 +295,11 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function updateElement(\n returnFiber : Fiber,\n- current : ?Fiber,\n+ current : Fiber | null,\n element : ReactElement,\n priority : PriorityLevel\n ) : Fiber {\n- if (current == null || current.type !== element.type) {\n+ if (current === null || current.type !== element.type) {\n \/\/ Insert\n const created = createFiberFromElement(element, priority);\n created.ref = coerceRef(current, element);\n@@ -321,12 +321,12 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function updateCoroutine(\n returnFiber : Fiber,\n- current : ?Fiber,\n+ current : Fiber | null,\n coroutine : ReactCoroutine,\n priority : PriorityLevel\n ) : Fiber {\n \/\/ TODO: Should this also compare handler to determine whether to reuse?\n- if (current == null || current.tag !== CoroutineComponent) {\n+ if (current === null || current.tag !== CoroutineComponent) {\n \/\/ Insert\n const created = createFiberFromCoroutine(coroutine, priority);\n created.return = returnFiber;\n@@ -342,11 +342,11 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function updateYield(\n returnFiber : Fiber,\n- current : ?Fiber,\n+ current : Fiber | null,\n yieldNode : ReactYield,\n priority : PriorityLevel\n ) : Fiber {\n- if (current == null || current.tag !== YieldComponent) {\n+ if (current === null || current.tag !== YieldComponent) {\n \/\/ Insert\n const created = createFiberFromYield(yieldNode, priority);\n created.type = yieldNode.value;\n@@ -363,12 +363,12 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function updatePortal(\n returnFiber : Fiber,\n- current : ?Fiber,\n+ current : Fiber | null,\n portal : ReactPortal,\n priority : PriorityLevel\n ) : Fiber {\n if (\n- current == null ||\n+ current === null ||\n current.tag !== HostPortal ||\n current.stateNode.containerInfo !== portal.containerInfo ||\n current.stateNode.implementation !== portal.implementation\n@@ -388,11 +388,11 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function updateFragment(\n returnFiber : Fiber,\n- current : ?Fiber,\n+ current : Fiber | null,\n fragment : Iterable<*>,\n priority : PriorityLevel\n ) : Fiber {\n- if (current == null || current.tag !== Fragment) {\n+ if (current === null || current.tag !== Fragment) {\n \/\/ Insert\n const created = createFiberFromFragment(fragment, priority);\n created.return = returnFiber;\n@@ -410,7 +410,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n returnFiber : Fiber,\n newChild : any,\n priority : PriorityLevel\n- ) : ?Fiber {\n+ ) : Fiber | null {\n if (typeof newChild === 'string' || typeof newChild === 'number') {\n \/\/ Text nodes doesn't have keys. If the previous node is implicitly keyed\n \/\/ we can continue to replace it without aborting even if it is not a text\n@@ -463,13 +463,13 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function updateSlot(\n returnFiber : Fiber,\n- oldFiber : ?Fiber,\n+ oldFiber : Fiber | null,\n newChild : any,\n priority : PriorityLevel\n- ) : ?Fiber {\n+ ) : Fiber | null {\n \/\/ Update the fiber if the keys match, otherwise return null.\n \n- const key = oldFiber ? oldFiber.key : null;\n+ const key = oldFiber !== null ? oldFiber.key : null;\n \n if (typeof newChild === 'string' || typeof newChild === 'number') {\n \/\/ Text nodes doesn't have keys. If the previous node is implicitly keyed\n@@ -540,7 +540,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n newIdx : number,\n newChild : any,\n priority : PriorityLevel\n- ) : ?Fiber {\n+ ) : Fiber | null {\n \n if (typeof newChild === 'string' || typeof newChild === 'number') {\n \/\/ Text nodes doesn't have keys, so we neither have to check the old nor\n@@ -596,7 +596,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n knownKeys : Set | null\n ) : Set | null {\n if (__DEV__) {\n- if (typeof child !== 'object' || child == null) {\n+ if (typeof child !== 'object' || child === null) {\n return knownKeys;\n }\n switch (child.$$typeof) {\n@@ -607,7 +607,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n if (typeof key !== 'string') {\n break;\n }\n- if (knownKeys == null) {\n+ if (knownKeys === null) {\n knownKeys = new Set();\n knownKeys.add(key);\n break;\n@@ -634,9 +634,9 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function reconcileChildrenArray(\n returnFiber : Fiber,\n- currentFirstChild : ?Fiber,\n+ currentFirstChild : Fiber | null,\n newChildren : Array<*>,\n- priority : PriorityLevel) : ?Fiber {\n+ priority : PriorityLevel) : Fiber | null {\n \n \/\/ This algorithm can't optimize by searching from boths ends since we\n \/\/ don't have backpointers on fibers. I'm trying to see how far we can get\n@@ -666,21 +666,19 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n }\n }\n \n- let resultingFirstChild : ?Fiber = null;\n- let previousNewFiber : ?Fiber = null;\n+ let resultingFirstChild : Fiber | null = null;\n+ let previousNewFiber : Fiber | null = null;\n \n let oldFiber = currentFirstChild;\n let lastPlacedIndex = 0;\n let newIdx = 0;\n let nextOldFiber = null;\n- for (; oldFiber && newIdx < newChildren.length; newIdx++) {\n- if (oldFiber) {\n- if (oldFiber.index > newIdx) {\n- nextOldFiber = oldFiber;\n- oldFiber = null;\n- } else {\n- nextOldFiber = oldFiber.sibling;\n- }\n+ for (; oldFiber !== null && newIdx < newChildren.length; newIdx++) {\n+ if (oldFiber.index > newIdx) {\n+ nextOldFiber = oldFiber;\n+ oldFiber = null;\n+ } else {\n+ nextOldFiber = oldFiber.sibling;\n }\n const newFiber = updateSlot(\n returnFiber,\n@@ -688,25 +686,25 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n newChildren[newIdx],\n priority\n );\n- if (!newFiber) {\n+ if (newFiber === null) {\n \/\/ TODO: This breaks on empty slots like null children. That's\n \/\/ unfortunate because it triggers the slow path all the time. We need\n \/\/ a better way to communicate whether this was a miss or null,\n \/\/ boolean, undefined, etc.\n- if (!oldFiber) {\n+ if (oldFiber === null) {\n oldFiber = nextOldFiber;\n }\n break;\n }\n if (shouldTrackSideEffects) {\n- if (oldFiber && !newFiber.alternate) {\n+ if (oldFiber && newFiber.alternate === null) {\n \/\/ We matched the slot, but we didn't reuse the existing fiber, so we\n \/\/ need to delete the existing child.\n deleteChild(returnFiber, oldFiber);\n }\n }\n lastPlacedIndex = placeChild(newFiber, lastPlacedIndex, newIdx);\n- if (!previousNewFiber) {\n+ if (previousNewFiber === null) {\n \/\/ TODO: Move out of the loop. This only happens for the first run.\n resultingFirstChild = newFiber;\n } else {\n@@ -726,7 +724,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n return resultingFirstChild;\n }\n \n- if (!oldFiber) {\n+ if (oldFiber === null) {\n \/\/ If we don't have any more existing children we can choose a fast path\n \/\/ since the rest will all be insertions.\n for (; newIdx < newChildren.length; newIdx++) {\n@@ -739,7 +737,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n continue;\n }\n lastPlacedIndex = placeChild(newFiber, lastPlacedIndex, newIdx);\n- if (!previousNewFiber) {\n+ if (previousNewFiber === null) {\n \/\/ TODO: Move out of the loop. This only happens for the first run.\n resultingFirstChild = newFiber;\n } else {\n@@ -764,7 +762,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n );\n if (newFiber) {\n if (shouldTrackSideEffects) {\n- if (newFiber.alternate) {\n+ if (newFiber.alternate !== null) {\n \/\/ The new fiber is a work in progress, but if there exists a\n \/\/ current, that means that we reused the fiber. We need to delete\n \/\/ it from the child list so that we don't add it to the deletion\n@@ -775,7 +773,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n }\n }\n lastPlacedIndex = placeChild(newFiber, lastPlacedIndex, newIdx);\n- if (!previousNewFiber) {\n+ if (previousNewFiber === null) {\n resultingFirstChild = newFiber;\n } else {\n previousNewFiber.sibling = newFiber;\n@@ -795,9 +793,9 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function reconcileChildrenIterator(\n returnFiber : Fiber,\n- currentFirstChild : ?Fiber,\n+ currentFirstChild : Fiber | null,\n newChildrenIterable : Iterable<*>,\n- priority : PriorityLevel) : ?Fiber {\n+ priority : PriorityLevel) : Fiber | null {\n \n \/\/ This is the same implementation as reconcileChildrenArray(),\n \/\/ but using the iterator instead.\n@@ -852,8 +850,8 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n 'An iterable object provided no iterator.',\n );\n \n- let resultingFirstChild : ?Fiber = null;\n- let previousNewFiber : ?Fiber = null;\n+ let resultingFirstChild : Fiber | null = null;\n+ let previousNewFiber : Fiber | null = null;\n \n let oldFiber = currentFirstChild;\n let lastPlacedIndex = 0;\n@@ -861,14 +859,12 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n let nextOldFiber = null;\n \n let step = newChildren.next();\n- for (; oldFiber && !step.done; newIdx++, step = newChildren.next()) {\n- if (oldFiber) {\n- if (oldFiber.index > newIdx) {\n- nextOldFiber = oldFiber;\n- oldFiber = null;\n- } else {\n- nextOldFiber = oldFiber.sibling;\n- }\n+ for (; oldFiber !== null && !step.done; newIdx++, step = newChildren.next()) {\n+ if (oldFiber.index > newIdx) {\n+ nextOldFiber = oldFiber;\n+ oldFiber = null;\n+ } else {\n+ nextOldFiber = oldFiber.sibling;\n }\n const newFiber = updateSlot(\n returnFiber,\n@@ -876,7 +872,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n step.value,\n priority\n );\n- if (!newFiber) {\n+ if (newFiber === null) {\n \/\/ TODO: This breaks on empty slots like null children. That's\n \/\/ unfortunate because it triggers the slow path all the time. We need\n \/\/ a better way to communicate whether this was a miss or null,\n@@ -887,14 +883,14 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n break;\n }\n if (shouldTrackSideEffects) {\n- if (oldFiber && !newFiber.alternate) {\n+ if (oldFiber && newFiber.alternate === null) {\n \/\/ We matched the slot, but we didn't reuse the existing fiber, so we\n \/\/ need to delete the existing child.\n deleteChild(returnFiber, oldFiber);\n }\n }\n lastPlacedIndex = placeChild(newFiber, lastPlacedIndex, newIdx);\n- if (!previousNewFiber) {\n+ if (previousNewFiber === null) {\n \/\/ TODO: Move out of the loop. This only happens for the first run.\n resultingFirstChild = newFiber;\n } else {\n@@ -914,7 +910,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n return resultingFirstChild;\n }\n \n- if (!oldFiber) {\n+ if (oldFiber === null) {\n \/\/ If we don't have any more existing children we can choose a fast path\n \/\/ since the rest will all be insertions.\n for (; !step.done; newIdx++, step = newChildren.next()) {\n@@ -923,11 +919,11 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n step.value,\n priority\n );\n- if (!newFiber) {\n+ if (newFiber === null) {\n continue;\n }\n lastPlacedIndex = placeChild(newFiber, lastPlacedIndex, newIdx);\n- if (!previousNewFiber) {\n+ if (previousNewFiber === null) {\n \/\/ TODO: Move out of the loop. This only happens for the first run.\n resultingFirstChild = newFiber;\n } else {\n@@ -950,9 +946,9 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n step.value,\n priority\n );\n- if (newFiber) {\n+ if (newFiber !== null) {\n if (shouldTrackSideEffects) {\n- if (newFiber.alternate) {\n+ if (newFiber.alternate !== null) {\n \/\/ The new fiber is a work in progress, but if there exists a\n \/\/ current, that means that we reused the fiber. We need to delete\n \/\/ it from the child list so that we don't add it to the deletion\n@@ -963,7 +959,7 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n }\n }\n lastPlacedIndex = placeChild(newFiber, lastPlacedIndex, newIdx);\n- if (!previousNewFiber) {\n+ if (previousNewFiber === null) {\n resultingFirstChild = newFiber;\n } else {\n previousNewFiber.sibling = newFiber;\n@@ -983,13 +979,13 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function reconcileSingleTextNode(\n returnFiber : Fiber,\n- currentFirstChild : ?Fiber,\n+ currentFirstChild : Fiber | null,\n textContent : string,\n priority : PriorityLevel\n ) : Fiber {\n \/\/ There's no need to check for keys on text nodes since we don't have a\n \/\/ way to define them.\n- if (currentFirstChild && currentFirstChild.tag === HostText) {\n+ if (currentFirstChild !== null && currentFirstChild.tag === HostText) {\n \/\/ We already have an existing node so let's just update it and delete\n \/\/ the rest.\n deleteRemainingChildren(returnFiber, currentFirstChild.sibling);\n@@ -1008,13 +1004,13 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function reconcileSingleElement(\n returnFiber : Fiber,\n- currentFirstChild : ?Fiber,\n+ currentFirstChild : Fiber | null,\n element : ReactElement,\n priority : PriorityLevel\n ) : Fiber {\n const key = element.key;\n let child = currentFirstChild;\n- while (child) {\n+ while (child !== null) {\n \/\/ TODO: If key === null and child.key === null, then this only applies to\n \/\/ the first item in the list.\n if (child.key === key) {\n@@ -1047,13 +1043,13 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function reconcileSingleCoroutine(\n returnFiber : Fiber,\n- currentFirstChild : ?Fiber,\n+ currentFirstChild : Fiber | null,\n coroutine : ReactCoroutine,\n priority : PriorityLevel\n ) : Fiber {\n const key = coroutine.key;\n let child = currentFirstChild;\n- while (child) {\n+ while (child !== null) {\n \/\/ TODO: If key === null and child.key === null, then this only applies to\n \/\/ the first item in the list.\n if (child.key === key) {\n@@ -1080,13 +1076,13 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function reconcileSingleYield(\n returnFiber : Fiber,\n- currentFirstChild : ?Fiber,\n+ currentFirstChild : Fiber | null,\n yieldNode : ReactYield,\n priority : PriorityLevel\n ) : Fiber {\n \/\/ There's no need to check for keys on yields since they're stateless.\n let child = currentFirstChild;\n- if (child) {\n+ if (child !== null) {\n if (child.tag === YieldComponent) {\n deleteRemainingChildren(returnFiber, child.sibling);\n const existing = useFiber(child, priority);\n@@ -1106,13 +1102,13 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \n function reconcileSinglePortal(\n returnFiber : Fiber,\n- currentFirstChild : ?Fiber,\n+ currentFirstChild : Fiber | null,\n portal : ReactPortal,\n priority : PriorityLevel\n ) : Fiber {\n const key = portal.key;\n let child = currentFirstChild;\n- while (child) {\n+ while (child !== null) {\n \/\/ TODO: If key === null and child.key === null, then this only applies to\n \/\/ the first item in the list.\n if (child.key === key) {\n@@ -1146,10 +1142,10 @@ function ChildReconciler(shouldClone, shouldTrackSideEffects) {\n \/\/ children and the parent.\n function reconcileChildFibers(\n returnFiber : Fiber,\n- currentFirstChild : ?Fiber,\n+ currentFirstChild : Fiber | null,\n newChild : any,\n priority : PriorityLevel\n- ) : ?Fiber {\n+ ) : Fiber | null {\n \/\/ This function is not recursive.\n \/\/ If the top level item is an array, we treat it as a set of children,\n \/\/ not as a fragment. Nested arrays on the other hand will be treated as\n@@ -1329,11 +1325,11 @@ exports.reconcileChildFibersInPlace = ChildReconciler(false, true);\n \n exports.mountChildFibersInPlace = ChildReconciler(false, false);\n \n-exports.cloneChildFibers = function(current : ?Fiber, workInProgress : Fiber) : void {\n+exports.cloneChildFibers = function(current : Fiber | null, workInProgress : Fiber) : void {\n if (!workInProgress.child) {\n return;\n }\n- if (current && workInProgress.child === current.child) {\n+ if (current !== null && workInProgress.child === current.child) {\n \/\/ We use workInProgress.child since that lets Flow know that it can't be\n \/\/ null since we validated that already. However, as the line above suggests\n \/\/ they're actually the same thing.\n@@ -1349,7 +1345,7 @@ exports.cloneChildFibers = function(current : ?Fiber, workInProgress : Fiber) :\n workInProgress.child = newChild;\n \n newChild.return = workInProgress;\n- while (currentChild.sibling) {\n+ while (currentChild.sibling !== null) {\n currentChild = currentChild.sibling;\n newChild = newChild.sibling = cloneFiber(\n currentChild,\n@@ -1365,7 +1361,7 @@ exports.cloneChildFibers = function(current : ?Fiber, workInProgress : Fiber) :\n \/\/ need to clone. We need to reset the return fiber though since we'll\n \/\/ traverse down into them.\n let child = workInProgress.child;\n- while (child) {\n+ while (child !== null) {\n child.return = workInProgress;\n child = child.sibling;\n }\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactDebugCurrentFiber.js b\/src\/renderers\/shared\/fiber\/ReactDebugCurrentFiber.js\nindex c1ce29ea1c..d857e5f2dd 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactDebugCurrentFiber.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactDebugCurrentFiber.js\n@@ -22,7 +22,7 @@ if (__DEV__) {\n function getCurrentFiberOwnerName() : string | null {\n if (__DEV__) {\n const fiber = ReactDebugCurrentFiber.current;\n- if (fiber == null) {\n+ if (fiber === null) {\n return null;\n }\n if (fiber._debugOwner != null) {\n@@ -35,7 +35,7 @@ function getCurrentFiberOwnerName() : string | null {\n function getCurrentFiberStackAddendum() : string | null {\n if (__DEV__) {\n const fiber = ReactDebugCurrentFiber.current;\n- if (fiber == null) {\n+ if (fiber === null) {\n return null;\n }\n \/\/ Safe because if current fiber exists, we are reconciling,\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactFiber.js b\/src\/renderers\/shared\/fiber\/ReactFiber.js\nindex 6af37269e7..d7ecf74371 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactFiber.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactFiber.js\n@@ -93,11 +93,11 @@ export type Fiber = {\n \/\/ This is effectively the parent, but there can be multiple parents (two)\n \/\/ so this is only the parent of the thing we're currently processing.\n \/\/ It is conceptually the same as the return address of a stack frame.\n- return: ?Fiber,\n+ return: Fiber | null,\n \n \/\/ Singly Linked List Tree Structure.\n- child: ?Fiber,\n- sibling: ?Fiber,\n+ child: Fiber | null,\n+ sibling: Fiber | null,\n index: number,\n \n \/\/ The ref last used to attach this node.\n@@ -119,13 +119,13 @@ export type Fiber = {\n effectTag: TypeOfSideEffect,\n \n \/\/ Singly linked list fast path to the next fiber with side-effects.\n- nextEffect: ?Fiber,\n+ nextEffect: Fiber | null,\n \n \/\/ The first and last fiber with side-effect within this subtree. This allows\n \/\/ us to reuse a slice of the linked list when we reuse the work done within\n \/\/ this fiber.\n- firstEffect: ?Fiber,\n- lastEffect: ?Fiber,\n+ firstEffect: Fiber | null,\n+ lastEffect: Fiber | null,\n \n \/\/ This will be used to quickly determine if a subtree has no pending changes.\n pendingWorkPriority: PriorityLevel,\n@@ -139,19 +139,19 @@ export type Fiber = {\n \/\/ priority, then we need to store the progressed work somewhere. This holds\n \/\/ the started child set until we need to get back to working on it. It may\n \/\/ or may not be the same as the \"current\" child.\n- progressedChild: ?Fiber,\n+ progressedChild: Fiber | null,\n \n \/\/ When we reconcile children onto progressedChild it is possible that we have\n \/\/ to delete some child fibers. We need to keep track of this side-effects so\n \/\/ that if we continue later on, we have to include those effects. Deletions\n \/\/ are added in the reverse order from sibling pointers.\n- progressedFirstDeletion: ?Fiber,\n- progressedLastDeletion: ?Fiber,\n+ progressedFirstDeletion: Fiber | null,\n+ progressedLastDeletion: Fiber | null,\n \n \/\/ This is a pooled version of a Fiber. Every fiber that gets updated will\n \/\/ eventually have a pair. There are cases when we can clean up pairs to save\n \/\/ memory if we need to.\n- alternate: ?Fiber,\n+ alternate: Fiber | null,\n \n \/\/ Conceptual aliases\n \/\/ workInProgress : Fiber -> alternate The alternate used for reuse happens\n@@ -249,7 +249,7 @@ exports.cloneFiber = function(fiber : Fiber, priorityLevel : PriorityLevel) : Fi\n \/\/ objects for things that are never updated. It also allow us to reclaim the\n \/\/ extra memory if needed.\n let alt = fiber.alternate;\n- if (alt) {\n+ if (alt !== null) {\n \/\/ If we clone, then we do so from the \"current\" state. The current state\n \/\/ can't have any side-effects that are still valid so we reset just to be\n \/\/ sure.\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactFiberBeginWork.js b\/src\/renderers\/shared\/fiber\/ReactFiberBeginWork.js\nindex 947ba6ed24..ffe68983d4 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactFiberBeginWork.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactFiberBeginWork.js\n@@ -102,7 +102,7 @@ module.exports = function(\n \/\/ We now have clones. Let's store them as the currently progressed work.\n workInProgress.progressedChild = workInProgress.child;\n workInProgress.progressedPriority = priorityLevel;\n- if (current) {\n+ if (current !== null) {\n \/\/ We also store it on the current. When the alternate swaps in we can\n \/\/ continue from this point.\n current.progressedChild = workInProgress.progressedChild;\n@@ -131,7 +131,7 @@ module.exports = function(\n \/\/ At this point any memoization is no longer valid since we'll have changed\n \/\/ the children.\n workInProgress.memoizedProps = null;\n- if (!current) {\n+ if (current === null) {\n \/\/ If this is a fresh new component that hasn't been rendered yet, we\n \/\/ won't update its child set by applying minimal side-effects. Instead,\n \/\/ we will add them all to the child before it gets rendered. That means\n@@ -191,9 +191,9 @@ module.exports = function(\n return workInProgress.child;\n }\n \n- function markRef(current : ?Fiber, workInProgress : Fiber) {\n+ function markRef(current : Fiber | null, workInProgress : Fiber) {\n const ref = workInProgress.ref;\n- if (ref && (!current || current.ref !== ref)) {\n+ if (ref !== null && (!current || current.ref !== ref)) {\n \/\/ Schedule a Ref effect\n workInProgress.effectTag |= Ref;\n }\n@@ -211,7 +211,7 @@ module.exports = function(\n nextProps = memoizedProps;\n }\n } else {\n- if (nextProps == null || memoizedProps === nextProps) {\n+ if (nextProps === null || memoizedProps === nextProps) {\n return bailoutOnAlreadyFinishedWork(current, workInProgress);\n }\n \/\/ TODO: Disable this before release, since it is not part of the public API\n@@ -240,14 +240,14 @@ module.exports = function(\n return workInProgress.child;\n }\n \n- function updateClassComponent(current : ?Fiber, workInProgress : Fiber, priorityLevel : PriorityLevel) {\n+ function updateClassComponent(current : Fiber | null, workInProgress : Fiber, priorityLevel : PriorityLevel) {\n \/\/ Push context providers early to prevent context stack mismatches.\n \/\/ During mounting we don't know the child context yet as the instance doesn't exist.\n \/\/ We will invalidate the child context in finishClassComponent() right after rendering.\n const hasContext = pushContextProvider(workInProgress);\n \n let shouldUpdate;\n- if (!current) {\n+ if (current === null) {\n if (!workInProgress.stateNode) {\n \/\/ In the initial pass we might need to construct the instance.\n constructClassInstance(workInProgress);\n@@ -264,7 +264,7 @@ module.exports = function(\n }\n \n function finishClassComponent(\n- current : ?Fiber,\n+ current : Fiber | null,\n workInProgress : Fiber,\n shouldUpdate : boolean,\n hasContext : boolean,\n@@ -314,7 +314,7 @@ module.exports = function(\n pushHostContainer(workInProgress, root.containerInfo);\n \n const updateQueue = workInProgress.updateQueue;\n- if (updateQueue) {\n+ if (updateQueue !== null) {\n const prevState = workInProgress.memoizedState;\n const state = beginUpdateQueue(workInProgress, updateQueue, null, prevState, null, priorityLevel);\n if (prevState === state) {\n@@ -335,7 +335,7 @@ module.exports = function(\n pushHostContext(workInProgress);\n \n let nextProps = workInProgress.pendingProps;\n- const prevProps = current ? current.memoizedProps : null;\n+ const prevProps = current !== null ? current.memoizedProps : null;\n const memoizedProps = workInProgress.memoizedProps;\n if (hasContextChanged()) {\n \/\/ Normally we can bail out on props equality but if context has changed\n@@ -359,7 +359,7 @@ module.exports = function(\n \/\/ that is a bit tricky since workInProgress and current can have\n \/\/ different \"hidden\" settings.\n let child = workInProgress.progressedChild;\n- while (child) {\n+ while (child !== null) {\n \/\/ To ensure that this subtree gets its priority reset, the children\n \/\/ need to be reset.\n child.pendingWorkPriority = OffscreenPriority;\n@@ -409,16 +409,16 @@ module.exports = function(\n \/\/ Reconcile the children and stash them for later work.\n reconcileChildrenAtPriority(current, workInProgress, nextChildren, OffscreenPriority);\n memoizeProps(workInProgress, nextProps);\n- workInProgress.child = current ? current.child : null;\n+ workInProgress.child = current !== null ? current.child : null;\n \n- if (!current) {\n+ if (current === null) {\n \/\/ If this doesn't have a current we won't track it for placement\n \/\/ effects. However, when we come back around to this we have already\n \/\/ inserted the parent which means that we'll infact need to make this a\n \/\/ placement.\n \/\/ TODO: There has to be a better solution to this problem.\n let child = workInProgress.progressedChild;\n- while (child) {\n+ while (child !== null) {\n child.effectTag = Placement;\n child = child.sibling;\n }\n@@ -464,7 +464,7 @@ module.exports = function(\n value = fn(props, context);\n }\n \n- if (typeof value === 'object' && value && typeof value.render === 'function') {\n+ if (typeof value === 'object' && value !== null && typeof value.render === 'function') {\n \/\/ Proceed under the assumption that this is a class instance\n workInProgress.tag = ClassComponent;\n \n@@ -479,7 +479,7 @@ module.exports = function(\n \/\/ Proceed under the assumption that this is a functional component\n workInProgress.tag = FunctionalComponent;\n if (__DEV__) {\n- if (workInProgress.ref != null) {\n+ if (workInProgress.ref !== null) {\n let info = '';\n const ownerName = ReactDebugCurrentFiber.getCurrentFiberOwnerName();\n if (ownerName) {\n@@ -517,7 +517,7 @@ module.exports = function(\n if (nextCoroutine === null) {\n nextCoroutine = current && current.memoizedProps;\n invariant(\n- nextCoroutine != null,\n+ nextCoroutine !== null,\n 'We should always have pending or current props. This error is ' +\n 'likely caused by a bug in React. Please file an issue.'\n );\n@@ -538,7 +538,7 @@ module.exports = function(\n \/\/ At this point any memoization is no longer valid since we'll have changed\n \/\/ the children.\n workInProgress.memoizedProps = null;\n- if (!current) {\n+ if (current === null) {\n workInProgress.stateNode = mountChildFibersInPlace(\n workInProgress,\n workInProgress.stateNode,\n@@ -592,7 +592,7 @@ module.exports = function(\n return bailoutOnAlreadyFinishedWork(current, workInProgress);\n }\n \n- if (!current) {\n+ if (current === null) {\n \/\/ Portals are special because we don't append the children during mount\n \/\/ but at commit. Therefore we need to track insertions which the normal\n \/\/ flow doesn't do during mount. This doesn't happen at the root because\n@@ -632,7 +632,7 @@ module.exports = function(\n }\n *\/\n \n- function bailoutOnAlreadyFinishedWork(current, workInProgress : Fiber) : ?Fiber {\n+ function bailoutOnAlreadyFinishedWork(current, workInProgress : Fiber) : Fiber | null {\n const priorityLevel = workInProgress.pendingWorkPriority;\n \/\/ TODO: We should ideally be able to bail out early if the children have no\n \/\/ more work to do. However, since we don't have a separation of this\n@@ -687,7 +687,7 @@ module.exports = function(\n \/\/ is handled by beginUpdateQueue.\n }\n \n- function beginWork(current : ?Fiber, workInProgress : Fiber, priorityLevel : PriorityLevel) : ?Fiber {\n+ function beginWork(current : Fiber | null, workInProgress : Fiber, priorityLevel : PriorityLevel) : Fiber | null {\n if (workInProgress.pendingWorkPriority === NoWork ||\n workInProgress.pendingWorkPriority > priorityLevel) {\n return bailoutOnLowPriority(current, workInProgress);\n@@ -744,7 +744,7 @@ module.exports = function(\n }\n }\n \n- function beginFailedWork(current : ?Fiber, workInProgress : Fiber, priorityLevel : PriorityLevel) {\n+ function beginFailedWork(current : Fiber | null, workInProgress : Fiber, priorityLevel : PriorityLevel) {\n invariant(\n workInProgress.tag === ClassComponent ||\n workInProgress.tag === HostRoot,\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactFiberClassComponent.js b\/src\/renderers\/shared\/fiber\/ReactFiberClassComponent.js\nindex d135b23531..94fbf67c21 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactFiberClassComponent.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactFiberClassComponent.js\n@@ -71,7 +71,7 @@ module.exports = function(\n };\n \n function checkShouldComponentUpdate(workInProgress, oldProps, newProps, oldState, newState, newContext) {\n- if (oldProps === null || (workInProgress.updateQueue && workInProgress.updateQueue.hasForceUpdate)) {\n+ if (oldProps === null || (workInProgress.updateQueue !== null && workInProgress.updateQueue.hasForceUpdate)) {\n \/\/ If the workInProgress already has an Update effect, return true\n return true;\n }\n@@ -208,10 +208,10 @@ module.exports = function(\n workInProgress.effectTag |= Update;\n }\n \n- function markUpdateIfAlreadyInProgress(current: ?Fiber, workInProgress : Fiber) {\n+ function markUpdateIfAlreadyInProgress(current: Fiber | null, workInProgress : Fiber) {\n \/\/ If an update was already in progress, we should schedule an Update\n \/\/ effect even though we're bailing out, so that cWU\/cDU are called.\n- if (current) {\n+ if (current !== null) {\n if (workInProgress.memoizedProps !== current.memoizedProps ||\n workInProgress.memoizedState !== current.memoizedState) {\n markUpdate(workInProgress);\n@@ -274,7 +274,7 @@ module.exports = function(\n \/\/ If we had additional state updates during this life-cycle, let's\n \/\/ process them now.\n const updateQueue = workInProgress.updateQueue;\n- if (updateQueue) {\n+ if (updateQueue !== null) {\n instance.state = beginUpdateQueue(\n workInProgress,\n updateQueue,\n@@ -343,7 +343,7 @@ module.exports = function(\n \/\/ They may be from componentWillMount() or from error boundary's setState()\n \/\/ during initial mounting.\n const newUpdateQueue = workInProgress.updateQueue;\n- if (newUpdateQueue) {\n+ if (newUpdateQueue !== null) {\n newInstance.state = beginUpdateQueue(\n workInProgress,\n newUpdateQueue,\n@@ -392,7 +392,7 @@ module.exports = function(\n const oldState = workInProgress.memoizedState;\n \/\/ TODO: Previous state can be null.\n let newState;\n- if (updateQueue) {\n+ if (updateQueue !== null) {\n newState = beginUpdateQueue(\n workInProgress,\n updateQueue,\n@@ -408,7 +408,7 @@ module.exports = function(\n if (oldProps === newProps &&\n oldState === newState &&\n !hasContextChanged() &&\n- !(updateQueue && updateQueue.hasForceUpdate)) {\n+ !(updateQueue !== null && updateQueue.hasForceUpdate)) {\n markUpdateIfAlreadyInProgress(current, workInProgress);\n return false;\n }\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactFiberCommitWork.js b\/src\/renderers\/shared\/fiber\/ReactFiberCommitWork.js\nindex 072c482355..f1a9dffec5 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactFiberCommitWork.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactFiberCommitWork.js\n@@ -38,7 +38,7 @@ var invariant = require('invariant');\n \n module.exports = function(\n config : HostConfig,\n- captureError : (failedFiber : Fiber, error: Error) => ?Fiber\n+ captureError : (failedFiber : Fiber, error: Error) => Fiber | null\n ) {\n \n const {\n@@ -65,7 +65,7 @@ module.exports = function(\n function safelyDetachRef(current : Fiber) {\n try {\n const ref = current.ref;\n- if (ref) {\n+ if (ref !== null) {\n ref(null);\n }\n } catch (error) {\n@@ -74,10 +74,10 @@ module.exports = function(\n }\n \n \/\/ Only called during update. It's ok to throw.\n- function detachRefIfNeeded(current : ?Fiber, finishedWork : Fiber) {\n+ function detachRefIfNeeded(current : Fiber | null, finishedWork : Fiber) {\n if (current) {\n const currentRef = current.ref;\n- if (currentRef && currentRef !== finishedWork.ref) {\n+ if (currentRef !== null && currentRef !== finishedWork.ref) {\n currentRef(null);\n }\n }\n@@ -85,7 +85,7 @@ module.exports = function(\n \n function getHostParent(fiber : Fiber) : I | C {\n let parent = fiber.return;\n- while (parent) {\n+ while (parent !== null) {\n switch (parent.tag) {\n case HostComponent:\n return parent.stateNode;\n@@ -105,7 +105,7 @@ module.exports = function(\n \n function getHostParentFiber(fiber : Fiber) : Fiber {\n let parent = fiber.return;\n- while (parent) {\n+ while (parent !== null) {\n if (isHostParent(parent)) {\n return parent;\n }\n@@ -134,8 +134,8 @@ module.exports = function(\n let node : Fiber = fiber;\n siblings: while (true) {\n \/\/ If we didn't find anything, let's try the next sibling.\n- while (!node.sibling) {\n- if (!node.return || isHostParent(node.return)) {\n+ while (node.sibling === null) {\n+ if (node.return === null || isHostParent(node.return)) {\n \/\/ If we pop out of the root or hit the parent the fiber we are the\n \/\/ last sibling.\n return null;\n@@ -153,7 +153,7 @@ module.exports = function(\n }\n \/\/ If we don't have a child, try the siblings instead.\n \/\/ We also skip portals because they are not part of this host tree.\n- if (!node.child || node.tag === HostPortal) {\n+ if (node.child === null || node.tag === HostPortal) {\n continue siblings;\n } else {\n node.child.return = node;\n@@ -211,7 +211,7 @@ module.exports = function(\n \/\/ If the insertion itself is a portal, then we don't want to traverse\n \/\/ down its children. Instead, we'll get insertions from each child in\n \/\/ the portal directly.\n- } else if (node.child) {\n+ } else if (node.child !== null) {\n node.child.return = node;\n node = node.child;\n continue;\n@@ -219,8 +219,8 @@ module.exports = function(\n if (node === finishedWork) {\n return;\n }\n- while (!node.sibling) {\n- if (!node.return || node.return === finishedWork) {\n+ while (node.sibling === null) {\n+ if (node.return === null || node.return === finishedWork) {\n return;\n }\n node = node.return;\n@@ -241,7 +241,7 @@ module.exports = function(\n commitUnmount(node);\n \/\/ Visit children because they may contain more composite or host nodes.\n \/\/ Skip portals because commitUnmount() currently visits them recursively.\n- if (node.child && node.tag !== HostPortal) {\n+ if (node.child !== null && node.tag !== HostPortal) {\n node.child.return = node;\n node = node.child;\n continue;\n@@ -249,8 +249,8 @@ module.exports = function(\n if (node === root) {\n return;\n }\n- while (!node.sibling) {\n- if (!node.return || node.return === root) {\n+ while (node.sibling === null) {\n+ if (node.return === null || node.return === root) {\n return;\n }\n node = node.return;\n@@ -276,7 +276,7 @@ module.exports = function(\n \/\/ We will reassign it back when we pop the portal on the way up.\n parent = node.stateNode.containerInfo;\n \/\/ Visit children because portals might contain host components.\n- if (node.child) {\n+ if (node.child !== null) {\n node.child.return = node;\n node = node.child;\n continue;\n@@ -284,7 +284,7 @@ module.exports = function(\n } else {\n commitUnmount(node);\n \/\/ Visit children because we may find more host components below.\n- if (node.child) {\n+ if (node.child !== null) {\n node.child.return = node;\n node = node.child;\n continue;\n@@ -293,8 +293,8 @@ module.exports = function(\n if (node === current) {\n return;\n }\n- while (!node.sibling) {\n- if (!node.return || node.return === current) {\n+ while (node.sibling === null) {\n+ if (node.return === null || node.return === current) {\n return;\n }\n node = node.return;\n@@ -364,7 +364,7 @@ module.exports = function(\n }\n }\n \n- function commitWork(current : ?Fiber, finishedWork : Fiber) : void {\n+ function commitWork(current : Fiber | null, finishedWork : Fiber) : void {\n switch (finishedWork.tag) {\n case ClassComponent: {\n detachRefIfNeeded(current, finishedWork);\n@@ -372,7 +372,7 @@ module.exports = function(\n }\n case HostComponent: {\n const instance : I = finishedWork.stateNode;\n- if (instance != null && current) {\n+ if (instance != null && current !== null) {\n \/\/ Commit the work prepared earlier.\n const newProps = finishedWork.memoizedProps;\n const oldProps = current.memoizedProps;\n@@ -380,7 +380,7 @@ module.exports = function(\n \/\/ TODO: Type the updateQueue to be specific to host components.\n const updatePayload : null | PL = (finishedWork.updateQueue : any);\n finishedWork.updateQueue = null;\n- if (updatePayload) {\n+ if (updatePayload !== null) {\n commitUpdate(instance, updatePayload, type, oldProps, newProps, finishedWork);\n }\n }\n@@ -389,7 +389,7 @@ module.exports = function(\n }\n case HostText: {\n invariant(\n- finishedWork.stateNode !== null && current != null,\n+ finishedWork.stateNode !== null && current !== null,\n 'This should only be done during updates. This error is likely ' +\n 'caused by a bug in React. Please file an issue.'\n );\n@@ -415,12 +415,12 @@ module.exports = function(\n }\n }\n \n- function commitLifeCycles(current : ?Fiber, finishedWork : Fiber) : void {\n+ function commitLifeCycles(current : Fiber | null, finishedWork : Fiber) : void {\n switch (finishedWork.tag) {\n case ClassComponent: {\n const instance = finishedWork.stateNode;\n if (finishedWork.effectTag & Update) {\n- if (!current) {\n+ if (current === null) {\n if (typeof instance.componentDidMount === 'function') {\n instance.componentDidMount();\n }\n@@ -432,14 +432,14 @@ module.exports = function(\n }\n }\n }\n- if ((finishedWork.effectTag & Callback) && finishedWork.updateQueue) {\n+ if ((finishedWork.effectTag & Callback) && finishedWork.updateQueue !== null) {\n commitCallbacks(finishedWork, finishedWork.updateQueue, instance);\n }\n return;\n }\n case HostRoot: {\n const updateQueue = finishedWork.updateQueue;\n- if (updateQueue) {\n+ if (updateQueue !== null) {\n const instance = finishedWork.child && finishedWork.child.stateNode;\n commitCallbacks(finishedWork, updateQueue, instance);\n }\n@@ -453,7 +453,7 @@ module.exports = function(\n \/\/ These effects should only be committed when components are first mounted,\n \/\/ aka when there is no current\/alternate.\n if (\n- !current &&\n+ current === null &&\n finishedWork.effectTag & Update\n ) {\n const type = finishedWork.type;\n@@ -486,7 +486,7 @@ module.exports = function(\n return;\n }\n const ref = finishedWork.ref;\n- if (ref) {\n+ if (ref !== null) {\n const instance = getPublicInstance(finishedWork.stateNode);\n ref(instance);\n }\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactFiberCompleteWork.js b\/src\/renderers\/shared\/fiber\/ReactFiberCompleteWork.js\nindex a8c8137f9a..c8a8888d60 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactFiberCompleteWork.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactFiberCompleteWork.js\n@@ -71,7 +71,7 @@ module.exports = function(\n \/\/ We now have clones. Let's store them as the currently progressed work.\n workInProgress.progressedChild = workInProgress.child;\n workInProgress.progressedPriority = priorityLevel;\n- if (current) {\n+ if (current !== null) {\n \/\/ We also store it on the current. When the alternate swaps in we can\n \/\/ continue from this point.\n current.progressedChild = workInProgress.progressedChild;\n@@ -90,7 +90,7 @@ module.exports = function(\n if (node) {\n node.return = workInProgress;\n }\n- while (node) {\n+ while (node !== null) {\n if (node.tag === HostComponent || node.tag === HostText ||\n node.tag === HostPortal) {\n invariant(\n@@ -99,13 +99,13 @@ module.exports = function(\n );\n } else if (node.tag === YieldComponent) {\n yields.push(node.type);\n- } else if (node.child) {\n+ } else if (node.child !== null) {\n node.child.return = node;\n node = node.child;\n continue;\n }\n- while (!node.sibling) {\n- if (!node.return || node.return === workInProgress) {\n+ while (node.sibling === null) {\n+ if (node.return === null || node.return === workInProgress) {\n return;\n }\n node = node.return;\n@@ -115,7 +115,7 @@ module.exports = function(\n }\n }\n \n- function moveCoroutineToHandlerPhase(current : ?Fiber, workInProgress : Fiber) {\n+ function moveCoroutineToHandlerPhase(current : Fiber | null, workInProgress : Fiber) {\n var coroutine = (workInProgress.memoizedProps : ?ReactCoroutine);\n invariant(\n coroutine,\n@@ -140,7 +140,7 @@ module.exports = function(\n var props = coroutine.props;\n var nextChildren = fn(props, yields);\n \n- var currentFirstChild = current ? current.child : null;\n+ var currentFirstChild = current !== null ? current.child : null;\n \/\/ Inherit the priority of the returnFiber.\n const priority = workInProgress.pendingWorkPriority;\n workInProgress.child = reconcileChildFibers(\n@@ -157,22 +157,22 @@ module.exports = function(\n \/\/ We only have the top Fiber that was created but we need recurse down its\n \/\/ children to find all the terminal nodes.\n let node = workInProgress.child;\n- while (node) {\n+ while (node !== null) {\n if (node.tag === HostComponent || node.tag === HostText) {\n appendInitialChild(parent, node.stateNode);\n } else if (node.tag === HostPortal) {\n \/\/ If we have a portal child, then we don't want to traverse\n \/\/ down its children. Instead, we'll get insertions from each child in\n \/\/ the portal directly.\n- } else if (node.child) {\n+ } else if (node.child !== null) {\n node = node.child;\n continue;\n }\n if (node === workInProgress) {\n return;\n }\n- while (!node.sibling) {\n- if (!node.return || node.return === workInProgress) {\n+ while (node.sibling === null) {\n+ if (node.return === null || node.return === workInProgress) {\n return;\n }\n node = node.return;\n@@ -181,7 +181,7 @@ module.exports = function(\n }\n }\n \n- function completeWork(current : ?Fiber, workInProgress : Fiber) : ?Fiber {\n+ function completeWork(current : Fiber | null, workInProgress : Fiber) : Fiber | null {\n if (__DEV__) {\n ReactDebugCurrentFiber.current = workInProgress;\n }\n@@ -208,7 +208,7 @@ module.exports = function(\n const rootContainerInstance = getRootHostContainer();\n const type = workInProgress.type;\n const newProps = workInProgress.memoizedProps;\n- if (current && workInProgress.stateNode != null) {\n+ if (current !== null && workInProgress.stateNode != null) {\n \/\/ If we have an alternate, that means this is an update and we need to\n \/\/ schedule a side-effect to do the updates.\n const oldProps = current.memoizedProps;\n@@ -268,7 +268,7 @@ module.exports = function(\n }\n \n workInProgress.stateNode = instance;\n- if (workInProgress.ref) {\n+ if (workInProgress.ref !== null) {\n \/\/ If there is a ref on a host node we need to schedule a callback\n workInProgress.effectTag |= Ref;\n }\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactFiberContext.js b\/src\/renderers\/shared\/fiber\/ReactFiberContext.js\nindex 322affe797..8b7383458b 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactFiberContext.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactFiberContext.js\n@@ -149,7 +149,7 @@ function processChildContext(fiber : Fiber, parentContext : Object, isReconcilin\n if (typeof instance.getChildContext !== 'function') {\n if (__DEV__) {\n const componentName = getComponentName(fiber);\n- \n+\n if (!warnedAboutMissingGetChildContext[componentName]) {\n warnedAboutMissingGetChildContext[componentName] = true;\n warning(\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactFiberHostContext.js b\/src\/renderers\/shared\/fiber\/ReactFiberHostContext.js\nindex 8abbc538d7..86c130c7cd 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactFiberHostContext.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactFiberHostContext.js\n@@ -44,14 +44,14 @@ module.exports = function(\n getRootHostContext,\n } = config;\n \n- let contextStackCursor : StackCursor = createCursor((null: ?CX));\n- let contextFiberStackCursor : StackCursor = createCursor((null: ?Fiber));\n- let rootInstanceStackCursor : StackCursor = createCursor((null: ?C));\n+ let contextStackCursor : StackCursor = createCursor((null: ?CX));\n+ let contextFiberStackCursor : StackCursor = createCursor((null: Fiber | null));\n+ let rootInstanceStackCursor : StackCursor = createCursor((null: ?C));\n \n function getRootHostContainer() : C {\n const rootInstance = rootInstanceStackCursor.current;\n invariant(\n- rootInstance != null,\n+ rootInstance !== null,\n 'Expected root container to exist. This error is likely caused by a ' +\n 'bug in React. Please file an issue.'\n );\n@@ -95,7 +95,9 @@ module.exports = function(\n 'a bug in React. Please file an issue.'\n );\n \n- const context = contextStackCursor.current || emptyObject;\n+ const context = contextStackCursor.current !== null ?\n+ contextStackCursor.current :\n+ emptyObject;\n const nextContext = getChildHostContext(context, fiber.type, rootInstance);\n \n \/\/ Don't push this Fiber's context unless it's unique.\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactFiberReconciler.js b\/src\/renderers\/shared\/fiber\/ReactFiberReconciler.js\nindex ab298f6b6a..1a429daf0a 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactFiberReconciler.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactFiberReconciler.js\n@@ -206,7 +206,7 @@ module.exports = function(\n \n findHostInstance(fiber : Fiber) : I | TI | null {\n const hostFiber = findCurrentHostFiber(fiber);\n- if (!hostFiber) {\n+ if (hostFiber === null) {\n return null;\n }\n return hostFiber.stateNode;\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactFiberRoot.js b\/src\/renderers\/shared\/fiber\/ReactFiberRoot.js\nindex 3bb55ff52d..f93dff9ba3 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactFiberRoot.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactFiberRoot.js\n@@ -24,10 +24,10 @@ export type FiberRoot = {\n \/\/ Determines if this root has already been added to the schedule for work.\n isScheduled: boolean,\n \/\/ The work schedule is a linked list.\n- nextScheduledRoot: ?FiberRoot,\n+ nextScheduledRoot: FiberRoot | null,\n \/\/ Top context object, used by renderSubtreeIntoContainer\n- context: ?Object,\n- pendingContext: ?Object,\n+ context: Object | null,\n+ pendingContext: Object | null,\n };\n \n exports.createFiberRoot = function(containerInfo : any) : FiberRoot {\ndiff --git a\/src\/renderers\/shared\/fiber\/ReactFiberScheduler.js b\/src\/renderers\/shared\/fiber\/ReactFiberScheduler.js\nindex d070cf4de4..e88126f696 100644\n--- a\/src\/renderers\/shared\/fiber\/ReactFiberScheduler.js\n+++ b\/src\/renderers\/shared\/fiber\/ReactFiberScheduler.js\n@@ -22,7 +22,7 @@ export type CapturedError = {\n componentStack : string,\n error : Error,\n errorBoundaryFound : boolean,\n- errorBoundaryName : ?string,\n+ errorBoundaryName : string | null,\n willRetry : boolean,\n };\n \n@@ -134,17 +134,17 @@ module.exports = function(config : HostConfig(config : HostConfig(config : HostConfig root.current.pendingWorkPriority)) {\n@@ -225,7 +225,7 @@ module.exports = function(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig TaskPriority) {\n+ if (deadline !== null && priorityLevel > TaskPriority) {\n \/\/ The deferred work loop will run until there's no time left in\n \/\/ the current frame.\n- while (nextUnitOfWork && !deadlineHasExpired) {\n+ while (nextUnitOfWork !== null && !deadlineHasExpired) {\n if (deadline.timeRemaining() > timeHeuristicForUnitOfWork) {\n nextUnitOfWork = performUnitOfWork(nextUnitOfWork);\n \/\/ In a deferred work batch, iff nextUnitOfWork returns null, we just\n \/\/ completed a root and a pendingCommit exists. Logically, we could\n \/\/ omit either of the checks in the following condition, but we need\n \/\/ both to satisfy Flow.\n- if (!nextUnitOfWork && pendingCommit) {\n+ if (nextUnitOfWork === null && pendingCommit !== null) {\n \/\/ If we have time, we should commit the work now.\n if (deadline.timeRemaining() > timeHeuristicForUnitOfWork) {\n commitAllWork(pendingCommit);\n@@ -690,11 +690,11 @@ module.exports = function(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig(config : HostConfig priorityLevel) {\n \/\/ Priority did not match. Update and keep going.\n@@ -1110,7 +1104,7 @@ module.exports = function(config : HostConfig(config : HostConfig(config : HostConfig

dillon1000/react

Files changed