mirror of
https://github.com/zhigang1992/react-native.git
synced 2026-02-07 17:27:56 +08:00
6e2f07fb81
Summary:
While adeveloper requests the emitter to emit an event, the emitter
may not emit the event immediately instead of putting the request
into a queue and process it later.
This diff allows the developer to provide a callback which will be called
when the event has been emitted.
For instance:
```
class NavigationContext {
push(nextRoute) {
var nextStack = this._stack.push(nextRoute);
this.emit(
'change',
{
reason: 'push',
nextStack: nextStack,
nextRoute: nextRoute,
},
this._onPush
);
}
_onPush(event){
if (event.defaultPrevented) {
return;
}
this._stack = event.nextStack;
this.emit('change');
}
}
```
121 lines
3.5 KiB
JavaScript
121 lines
3.5 KiB
JavaScript
/**
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* Copyright (c) 2015, Facebook, Inc. All rights reserved.
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*
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* Facebook, Inc. (“Facebook”) owns all right, title and interest, including
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* all intellectual property and other proprietary rights, in and to the React
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* Native CustomComponents software (the “Software”). Subject to your
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* compliance with these terms, you are hereby granted a non-exclusive,
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* worldwide, royalty-free copyright license to (1) use and copy the Software;
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* and (2) reproduce and distribute the Software as part of your own software
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* (“Your Software”). Facebook reserves all rights not expressly granted to
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* you in this license agreement.
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*
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* THE SOFTWARE AND DOCUMENTATION, IF ANY, ARE PROVIDED "AS IS" AND ANY EXPRESS
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* OR IMPLIED WARRANTIES (INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE) ARE DISCLAIMED.
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* IN NO EVENT SHALL FACEBOOK OR ITS AFFILIATES, OFFICERS, DIRECTORS OR
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* EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THE SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* @providesModule NavigationEvent
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* @flow
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*/
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'use strict';
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var invariant = require('invariant');
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class NavigationEventPool {
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_list: Array<any>;
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constructor() {
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this._list = [];
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}
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get(type: string, target: Object, data: any): NavigationEvent {
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var event;
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if (this._list.length > 0) {
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event = this._list.pop();
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event.constructor.call(event, type, target, data);
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} else {
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event = new NavigationEvent(type, target, data);
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}
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return event;
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}
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put(event: NavigationEvent) {
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this._list.push(event);
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}
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}
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var _navigationEventPool = new NavigationEventPool();
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class NavigationEvent {
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_data: any;
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_defaultPrevented: boolean;
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_disposed: boolean;
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_target: ?Object;
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_type: ?string;
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static pool(type: string, target: Object, data: any): NavigationEvent {
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return _navigationEventPool.get(type, target, data);
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}
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constructor(type: string, target: Object, data: any) {
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this._type = type;
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this._target = target;
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this._data = data;
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this._defaultPrevented = false;
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this._disposed = false;
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}
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/* $FlowFixMe - get/set properties not yet supported */
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get type(): string {
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return this._type;
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}
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/* $FlowFixMe - get/set properties not yet supported */
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get target(): Object {
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return this._target;
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}
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/* $FlowFixMe - get/set properties not yet supported */
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get data(): any {
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return this._data;
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}
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/* $FlowFixMe - get/set properties not yet supported */
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get defaultPrevented(): boolean {
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return this._defaultPrevented;
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}
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preventDefault(): void {
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this._defaultPrevented = true;
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}
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/**
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* Dispose the event.
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* NavigationEvent shall be disposed after being emitted by
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* `NavigationEventEmitter`.
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*/
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dispose(): void {
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invariant(!this._disposed, 'NavigationEvent is already disposed');
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this._disposed = true;
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// Clean up.
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this._type = null;
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this._target = null;
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this._data = null;
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this._defaultPrevented = false;
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// Put this back to the pool to reuse the instance.
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_navigationEventPool.put(this);
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}
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}
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module.exports = NavigationEvent;
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