Files
react/packages/shared/isValidElementType.js
Andrew Clark a0733fe13d pure (#13748)
* pure

A higher-order component version of the `React.PureComponent` class.
During an update, the previous props are compared to the new props. If
they are the same, React will skip rendering the component and
its children.

Unlike userspace implementations, `pure` will not add an additional
fiber to the tree.

The first argument must be a functional component; it does not work
with classes.

`pure` uses shallow comparison by default, like `React.PureComponent`.
A custom comparison can be passed as the second argument.

Co-authored-by: Andrew Clark <acdlite@fb.com>
Co-authored-by: Sophie Alpert <sophiebits@fb.com>

* Warn if first argument is not a functional component
2018-09-27 15:25:38 -07:00

41 lines
1.1 KiB
JavaScript

/**
* 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.
*
* @flow
*/
import {
REACT_CONCURRENT_MODE_TYPE,
REACT_CONTEXT_TYPE,
REACT_FORWARD_REF_TYPE,
REACT_FRAGMENT_TYPE,
REACT_PROFILER_TYPE,
REACT_PROVIDER_TYPE,
REACT_STRICT_MODE_TYPE,
REACT_PLACEHOLDER_TYPE,
REACT_PURE_TYPE,
} from 'shared/ReactSymbols';
export default function isValidElementType(type: mixed) {
return (
typeof type === 'string' ||
typeof type === 'function' ||
// Note: its typeof might be other than 'symbol' or 'number' if it's a polyfill.
type === REACT_FRAGMENT_TYPE ||
type === REACT_CONCURRENT_MODE_TYPE ||
type === REACT_PROFILER_TYPE ||
type === REACT_STRICT_MODE_TYPE ||
type === REACT_PLACEHOLDER_TYPE ||
(typeof type === 'object' &&
type !== null &&
(typeof type.then === 'function' ||
type.$$typeof === REACT_PURE_TYPE ||
type.$$typeof === REACT_PROVIDER_TYPE ||
type.$$typeof === REACT_CONTEXT_TYPE ||
type.$$typeof === REACT_FORWARD_REF_TYPE))
);
}