Function renderModelDestructive

packages/react-server/src/ReactFlightServer.js:3324–3938

(
  request: Request,
  task: Task,
  parent:
    | {+[propertyName: string | number]: ReactClientValue}
    | $ReadOnlyArray<ReactClientValue>,
  parentPropertyName: string,
  value: ReactClientValue,
)

}

function renderModelDestructive(
  request: Request,
  task: Task,
  parent:
    | {+[propertyName: string | number]: ReactClientValue}
    | $ReadOnlyArray<ReactClientValue>,
  parentPropertyName: string,
  value: ReactClientValue,
): ReactJSONValue {
  // Set the currently rendering model
  task.model = value;

  if (__DEV__) {
    if (parentPropertyName === __PROTO__) {
      callWithDebugContextInDEV(request, task, () => {
        console.error(
          'Expected not to serialize an object with own property `__proto__`. When parsed this property will be omitted.%s',
          describeObjectForErrorMessage(parent, parentPropertyName),
        );
      });
    }
  }

  // Special Symbol, that's very common.
  if (value === REACT_ELEMENT_TYPE) {
    return '$';
  }

  if (value === null) {
    return null;
  }

  if (typeof value === 'object') {
    switch ((value: any).$$typeof) {
      case REACT_ELEMENT_TYPE: {
        let elementReference = null;
        const writtenObjects = request.writtenObjects;
        if (task.keyPath !== null || task.implicitSlot) {
          // If we're in some kind of context we can't reuse the result of this render or
          // previous renders of this element. We only reuse elements if they're not wrapped
          // by another Server Component.
        } else {
          const existingReference = writtenObjects.get(value);
          if (existingReference !== undefined) {
            if (modelRoot === value) {
              // This is the ID we're currently emitting so we need to write it
              // once but if we discover it again, we refer to it by id.
              modelRoot = null;
            } else {
              // We've already emitted this as an outlined object, so we can refer to that by its
              // existing ID. TODO: We should use a lazy reference since, unlike plain objects,
              // elements might suspend so it might not have emitted yet even if we have the ID for
              // it. However, this creates an extra wrapper when it's not needed. We should really
              // detect whether this already was emitted and synchronously available. In that
              // case we can refer to it synchronously and only make it lazy otherwise.
              // We currently don't have a data structure that lets us see that though.
              return existingReference;
            }