/**

 * 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

 */

// ATTENTION

// When adding new symbols to this file,

// Please consider also adding to 'react-devtools-shared/src/backend/ReactSymbols'

// The Symbol used to tag the ReactElement-like types.

export const REACT_ELEMENT_TYPE: symbol = Symbol.for('react.element');

export const REACT_PORTAL_TYPE: symbol = Symbol.for('react.portal');

export const REACT_FRAGMENT_TYPE: symbol = Symbol.for('react.fragment');

export const REACT_STRICT_MODE_TYPE: symbol = Symbol.for('react.strict_mode');

export const REACT_PROFILER_TYPE: symbol = Symbol.for('react.profiler');

export const REACT_PROVIDER_TYPE: symbol = Symbol.for('react.provider');

export const REACT_CONTEXT_TYPE: symbol = Symbol.for('react.context');

export const REACT_SERVER_CONTEXT_TYPE: symbol = Symbol.for(

  'react.server_context',

);

export const REACT_FORWARD_REF_TYPE: symbol = Symbol.for('react.forward_ref');

export const REACT_SUSPENSE_TYPE: symbol = Symbol.for('react.suspense');

export const REACT_SUSPENSE_LIST_TYPE: symbol = Symbol.for(

  'react.suspense_list',

);

export const REACT_MEMO_TYPE: symbol = Symbol.for('react.memo');

export const REACT_LAZY_TYPE: symbol = Symbol.for('react.lazy');

export const REACT_SCOPE_TYPE: symbol = Symbol.for('react.scope');

export const REACT_DEBUG_TRACING_MODE_TYPE: symbol = Symbol.for(

  'react.debug_trace_mode',

);

export const REACT_OFFSCREEN_TYPE: symbol = Symbol.for('react.offscreen');

export const REACT_LEGACY_HIDDEN_TYPE: symbol = Symbol.for(

  'react.legacy_hidden',

);

export const REACT_CACHE_TYPE: symbol = Symbol.for('react.cache');

export const REACT_TRACING_MARKER_TYPE: symbol = Symbol.for(

  'react.tracing_marker',

);

export const REACT_SERVER_CONTEXT_DEFAULT_VALUE_NOT_LOADED: symbol = Symbol.for(

  'react.default_value',

);

export const REACT_MEMO_CACHE_SENTINEL: symbol = Symbol.for(

  'react.memo_cache_sentinel',

);

export const REACT_POSTPONE_TYPE: symbol = Symbol.for('react.postpone');

const MAYBE_ITERATOR_SYMBOL = Symbol.iterator;

const FAUX_ITERATOR_SYMBOL = '@@iterator';

export function getIteratorFn(maybeIterable: ?any): ?() => ?Iterator<any> {

  if (maybeIterable === null || typeof maybeIterable !== 'object') {

    return null;

  }

  const maybeIterator =

    (MAYBE_ITERATOR_SYMBOL && maybeIterable[MAYBE_ITERATOR_SYMBOL]) ||

    maybeIterable[FAUX_ITERATOR_SYMBOL];

  if (typeof maybeIterator === 'function') {

    return maybeIterator;

  }

  return null;

}