Function propagateContextChange

lib/assets/react-source/development/react.js:15665–15758

(workInProgress, context, changedBits, renderExpirationTime)

	  }
	}
	function propagateContextChange(workInProgress, context, changedBits, renderExpirationTime) {
	  var fiber = workInProgress.child;

	  if (fiber !== null) {
	    // Set the return pointer of the child to the work-in-progress fiber.
	    fiber.return = workInProgress;
	  }

	  while (fiber !== null) {
	    var nextFiber = void 0; // Visit this fiber.

	    var list = fiber.dependencies;

	    if (list !== null) {
	      nextFiber = fiber.child;
	      var dependency = list.firstContext;

	      while (dependency !== null) {
	        // Check if the context matches.
	        if (dependency.context === context && (dependency.observedBits & changedBits) !== 0) {
	          // Match! Schedule an update on this fiber.
	          if (fiber.tag === ClassComponent) {
	            // Schedule a force update on the work-in-progress.
	            var update = createUpdate(renderExpirationTime, null);
	            update.tag = ForceUpdate; // TODO: Because we don't have a work-in-progress, this will add the
	            // update to the current fiber, too, which means it will persist even if
	            // this render is thrown away. Since it's a race condition, not sure it's
	            // worth fixing.

	            enqueueUpdate(fiber, update);
	          }

	          if (fiber.expirationTime < renderExpirationTime) {
	            fiber.expirationTime = renderExpirationTime;
	          }

	          var alternate = fiber.alternate;

	          if (alternate !== null && alternate.expirationTime < renderExpirationTime) {
	            alternate.expirationTime = renderExpirationTime;
	          }

	          scheduleWorkOnParentPath(fiber.return, renderExpirationTime); // Mark the expiration time on the list, too.

	          if (list.expirationTime < renderExpirationTime) {
	            list.expirationTime = renderExpirationTime;
	          } // Since we already found a match, we can stop traversing the
	          // dependency list.


	          break;
	        }

	        dependency = dependency.next;
	      }
	    } else if (fiber.tag === ContextProvider) {
	      // Don't scan deeper if this is a matching provider
	      nextFiber = fiber.type === workInProgress.type ? null : fiber.child;