pushHostContext() — react Function Reference

Source Code

packages/react-reconciler/src/ReactFiberHostContext.js lines 96–129

function pushHostContext(fiber: Fiber): void {
  const stateHook: Hook | null = fiber.memoizedState;
  if (stateHook !== null) {
    // Propagate the current state to all the descendents.
    // We use Context as an implementation detail for this.
    //
    // NOTE: This assumes that there cannot be nested transition providers,
    // because the only renderer that implements this feature is React DOM,
    // and forms cannot be nested. If we did support nested providers, then
    // we would need to push a context value even for host fibers that
    // haven't been upgraded yet.
    const transitionStatus: TransitionStatus = stateHook.memoizedState;
    if (isPrimaryRenderer) {
      HostTransitionContext._currentValue = transitionStatus;
    } else {
      HostTransitionContext._currentValue2 = transitionStatus;
    }

    // Only provide context if this fiber has been upgraded by a host
    // transition. We use the same optimization for regular host context below.
    push(hostTransitionProviderCursor, fiber, fiber);
  }

  const context: HostContext = requiredContext(contextStackCursor.current);
  const nextContext = getChildHostContext(context, fiber.type);

  // Don't push this Fiber's context unless it's unique.
  if (context !== nextContext) {
    // Track the context and the Fiber that provided it.
    // This enables us to pop only Fibers that provide unique contexts.
    push(contextFiberStackCursor, fiber, fiber);
    push(contextStackCursor, nextContext, fiber);
  }
}