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/**
* @license
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
export interface ListenOptions {
event?: string;
capture?: boolean;
}
export class GrEventHelper {
constructor(readonly element: HTMLElement) {}
/**
* Add a callback to arbitrary event.
* The callback may return false to prevent event bubbling.
*/
on(event: string, callback: (event: Event) => boolean) {
return this._listen(this.element, callback, {event});
}
/**
* Alias for @see onClick
*/
onTap(callback: (event: Event) => boolean) {
return this.onClick(callback);
}
/**
* Add a callback to element click or touch.
* The callback may return false to prevent event bubbling.
*/
onClick(callback: (event: Event) => boolean) {
return this._listen(this.element, callback);
}
/**
* Alias for @see captureClick
*/
captureTap(callback: (event: Event) => boolean) {
this.captureClick(callback);
}
/**
* Add a callback to element click or touch ahead of normal flow.
* Callback is installed on parent during capture phase.
* https://www.w3.org/TR/DOM-Level-3-Events/#event-flow
* The callback may return false to cancel regular event listeners.
*/
captureClick(callback: (event: Event) => boolean) {
const parent = this.element.parentElement!;
return this._listen(parent, callback, {capture: true});
}
_listen(
container: HTMLElement,
callback: (event: Event) => boolean,
options?: ListenOptions | null
) {
const capture = options?.capture;
const event = options?.event || 'click';
const handler = (e: Event) => {
const path = e.composedPath();
if (!path) return;
if (path.indexOf(this.element) !== -1) {
let mayContinue = true;
try {
mayContinue = callback(e);
} catch (exception) {
console.warn(`Plugin error handing event: ${exception}`);
}
if (mayContinue === false) {
e.stopImmediatePropagation();
e.stopPropagation();
e.preventDefault();
}
}
};
container.addEventListener(event, handler, capture);
const unsubscribe = () =>
container.removeEventListener(event, handler, capture);
return unsubscribe;
}
}
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