Function ReactFiberHostContext

code/new-context-api/public/app.js:11248–11329

(config, stack)

var NO_CONTEXT = {};

var ReactFiberHostContext = function (config, stack) {
  var getChildHostContext = config.getChildHostContext,
      getRootHostContext = config.getRootHostContext;
  var createCursor = stack.createCursor,
      push = stack.push,
      pop = stack.pop;


  var contextStackCursor = createCursor(NO_CONTEXT);
  var contextFiberStackCursor = createCursor(NO_CONTEXT);
  var rootInstanceStackCursor = createCursor(NO_CONTEXT);

  function requiredContext(c) {
    !(c !== NO_CONTEXT) ? invariant(false, 'Expected host context to exist. This error is likely caused by a bug in React. Please file an issue.') : void 0;
    return c;
  }

  function getRootHostContainer() {
    var rootInstance = requiredContext(rootInstanceStackCursor.current);
    return rootInstance;
  }

  function pushHostContainer(fiber, nextRootInstance) {
    // Push current root instance onto the stack;
    // This allows us to reset root when portals are popped.
    push(rootInstanceStackCursor, nextRootInstance, fiber);

    var nextRootContext = getRootHostContext(nextRootInstance);

    // 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, nextRootContext, fiber);
  }

  function popHostContainer(fiber) {
    pop(contextStackCursor, fiber);
    pop(contextFiberStackCursor, fiber);
    pop(rootInstanceStackCursor, fiber);
  }

  function getHostContext() {
    var context = requiredContext(contextStackCursor.current);
    return context;
  }

  function pushHostContext(fiber) {
    var rootInstance = requiredContext(rootInstanceStackCursor.current);
    var context = requiredContext(contextStackCursor.current);
    var nextContext = getChildHostContext(context, fiber.type, rootInstance);

    // Don't push this Fiber's context unless it's unique.
    if (context === nextContext) {
      return;
    }

    // Track the context and the Fiber that provided it.
    // This enables us to pop only Fibers that provide unique contexts.