ReactIs.js — react Source File

Source Code

/**
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * @flow
 */

'use strict';

import {
  REACT_CONTEXT_TYPE,
  REACT_ELEMENT_TYPE,
  REACT_FORWARD_REF_TYPE,
  REACT_FRAGMENT_TYPE,
  REACT_LAZY_TYPE,
  REACT_MEMO_TYPE,
  REACT_PORTAL_TYPE,
  REACT_PROFILER_TYPE,
  REACT_CONSUMER_TYPE,
  REACT_STRICT_MODE_TYPE,
  REACT_SUSPENSE_TYPE,
  REACT_SUSPENSE_LIST_TYPE,
  REACT_VIEW_TRANSITION_TYPE,
  REACT_SCOPE_TYPE,
  REACT_LEGACY_HIDDEN_TYPE,
  REACT_TRACING_MARKER_TYPE,
} from 'shared/ReactSymbols';

import {
  enableScopeAPI,
  enableTransitionTracing,
  enableLegacyHidden,
  enableViewTransition,
} from 'shared/ReactFeatureFlags';

const REACT_CLIENT_REFERENCE: symbol = Symbol.for('react.client.reference');

export function typeOf(object: any): mixed {
  if (typeof object === 'object' && object !== null) {
    const $$typeof = object.$$typeof;
    switch ($$typeof) {
      case REACT_ELEMENT_TYPE:
        const type = object.type;

        switch (type) {
          case REACT_FRAGMENT_TYPE:
          case REACT_PROFILER_TYPE:
          case REACT_STRICT_MODE_TYPE:
          case REACT_SUSPENSE_TYPE:
          case REACT_SUSPENSE_LIST_TYPE:
          case REACT_VIEW_TRANSITION_TYPE:
            return type;
          default:
            const $$typeofType = type && type.$$typeof;

            switch ($$typeofType) {
              case REACT_CONTEXT_TYPE:
              case REACT_FORWARD_REF_TYPE:
// ... (113 more lines)