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',
);
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;
}