pomber / didact

A DIY guide to build your own React

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commitWork function should return after commitDeletion(anOldFiber, domParent)

1adybug opened this issue · comments

function commitWork(fiber) {
  if (!fiber) {
    return
  }

  let domParentFiber = fiber.parent
  while (!domParentFiber.dom) {
    domParentFiber = domParentFiber.parent
  }
  const domParent = domParentFiber.dom

  if (
    fiber.effectTag === "PLACEMENT" &&
    fiber.dom != null
  ) {
    domParent.appendChild(fiber.dom)
  } else if (
    fiber.effectTag === "UPDATE" &&
    fiber.dom != null
  ) {
    updateDom(
      fiber.dom,
      fiber.alternate.props,
      fiber.props
    )
  } else if (fiber.effectTag === "DELETION") {
    commitDeletion(fiber, domParent)

    // function should return at this moment
    return
  }

  commitWork(fiber.child)
  commitWork(fiber.sibling)
}

let's call the fiber to be deleted oldFiber

if commitWork function didnt return after commitDeletion(oldFiber, domParent), it will commitWork(oldFiber.child) and commitWork(oldFiber.sibling).

This may cause a terrible bug, because u dont know what type is oldFiber.child.effectTag or oldFiber.sibiling.effectTag

and commitWork function dont know the two fibers are old fibers and will treat them as current fiber to process.