mountIncompleteClassComponent() — react Function Reference

Source Code

packages/react-reconciler/src/ReactFiberBeginWork.js lines 2173–2210

function mountIncompleteClassComponent(
  _current: null | Fiber,
  workInProgress: Fiber,
  Component: any,
  nextProps: any,
  renderLanes: Lanes,
) {
  resetSuspendedCurrentOnMountInLegacyMode(_current, workInProgress);

  // Promote the fiber to a class and try rendering again.
  workInProgress.tag = ClassComponent;

  // The rest of this function is a fork of `updateClassComponent`

  // Push context providers early to prevent context stack mismatches.
  // During mounting we don't know the child context yet as the instance doesn't exist.
  // We will invalidate the child context in finishClassComponent() right after rendering.
  let hasContext;
  if (isLegacyContextProvider(Component)) {
    hasContext = true;
    pushLegacyContextProvider(workInProgress);
  } else {
    hasContext = false;
  }
  prepareToReadContext(workInProgress, renderLanes);

  constructClassInstance(workInProgress, Component, nextProps);
  mountClassInstance(workInProgress, Component, nextProps, renderLanes);

  return finishClassComponent(
    null,
    workInProgress,
    Component,
    true,
    hasContext,
    renderLanes,
  );
}