react-esm/dist-src/shared/ReactSymbols.js

React is a JavaScript library for building user interfaces.

/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * 
 */
// The Symbol used to tag the ReactElement-like types. If there is no native Symbol
// nor polyfill, then a plain number is used for performance.
const hasSymbol = typeof Symbol === 'function' && Symbol.for;
export const REACT_ELEMENT_TYPE = hasSymbol ? Symbol.for('react.element') : 0xeac7;
export const REACT_PORTAL_TYPE = hasSymbol ? Symbol.for('react.portal') : 0xeaca;
export const REACT_FRAGMENT_TYPE = hasSymbol ? Symbol.for('react.fragment') : 0xeacb;
export const REACT_STRICT_MODE_TYPE = hasSymbol ? Symbol.for('react.strict_mode') : 0xeacc;
export const REACT_PROFILER_TYPE = hasSymbol ? Symbol.for('react.profiler') : 0xead2;
export const REACT_PROVIDER_TYPE = hasSymbol ? Symbol.for('react.provider') : 0xeacd;
export const REACT_CONTEXT_TYPE = hasSymbol ? Symbol.for('react.context') : 0xeace;
export const REACT_ASYNC_MODE_TYPE = hasSymbol ? Symbol.for('react.async_mode') : 0xeacf;
export const REACT_CONCURRENT_MODE_TYPE = hasSymbol ? Symbol.for('react.concurrent_mode') : 0xeacf;
export const REACT_FORWARD_REF_TYPE = hasSymbol ? Symbol.for('react.forward_ref') : 0xead0;
export const REACT_SUSPENSE_TYPE = hasSymbol ? Symbol.for('react.suspense') : 0xead1;
export const REACT_MEMO_TYPE = hasSymbol ? Symbol.for('react.memo') : 0xead3;
export const REACT_LAZY_TYPE = hasSymbol ? Symbol.for('react.lazy') : 0xead4;
const MAYBE_ITERATOR_SYMBOL = typeof Symbol === 'function' && Symbol.iterator;
const FAUX_ITERATOR_SYMBOL = '@@iterator';
export function getIteratorFn(maybeIterable) {
  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;
}