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/**
* Copyright 2013-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*
*
*/
'use strict';
var ReactOwner = require('./ReactOwner');
var ReactRef = {};
function attachRef(ref, component, owner) {
if (typeof ref === 'function') {
ref(component.getPublicInstance());
} else {
// Legacy ref
ReactOwner.addComponentAsRefTo(component, ref, owner);
}
}
function detachRef(ref, component, owner) {
if (typeof ref === 'function') {
ref(null);
} else {
// Legacy ref
ReactOwner.removeComponentAsRefFrom(component, ref, owner);
}
}
ReactRef.attachRefs = function (instance, element) {
if (element === null || typeof element !== 'object') {
return;
}
var ref = element.ref;
if (ref != null) {
attachRef(ref, instance, element._owner);
}
};
ReactRef.shouldUpdateRefs = function (prevElement, nextElement) {
// If either the owner or a `ref` has changed, make sure the newest owner
// has stored a reference to `this`, and the previous owner (if different)
// has forgotten the reference to `this`. We use the element instead
// of the public this.props because the post processing cannot determine
// a ref. The ref conceptually lives on the element.
// TODO: Should this even be possible? The owner cannot change because
// it's forbidden by shouldUpdateReactComponent. The ref can change
// if you swap the keys of but not the refs. Reconsider where this check
// is made. It probably belongs where the key checking and
// instantiateReactComponent is done.
var prevRef = null;
var prevOwner = null;
if (prevElement !== null && typeof prevElement === 'object') {
prevRef = prevElement.ref;
prevOwner = prevElement._owner;
}
var nextRef = null;
var nextOwner = null;
if (nextElement !== null && typeof nextElement === 'object') {
nextRef = nextElement.ref;
nextOwner = nextElement._owner;
}
return prevRef !== nextRef ||
// If owner changes but we have an unchanged function ref, don't update refs
typeof nextRef === 'string' && nextOwner !== prevOwner;
};
ReactRef.detachRefs = function (instance, element) {
if (element === null || typeof element !== 'object') {
return;
}
var ref = element.ref;
if (ref != null) {
detachRef(ref, instance, element._owner);
}
};
module.exports = ReactRef;
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