iwmlib/3rdparty/hammer.propagating.js
2019-03-21 09:57:27 +01:00

232 lines
7.3 KiB
JavaScript

'use strict';
(function (factory) {
if (typeof define === 'function' && define.amd) {
// AMD. Register as an anonymous module.
define([], factory);
} else if (typeof exports === 'object') {
// Node. Does not work with strict CommonJS, but
// only CommonJS-like environments that support module.exports,
// like Node.
module.exports = factory();
} else {
// Browser globals (root is window)
window.propagating = factory();
}
}(function () {
var _firstTarget = null; // singleton, will contain the target element where the touch event started
/**
* Extend an Hammer.js instance with event propagation.
*
* Features:
* - Events emitted by hammer will propagate in order from child to parent
* elements.
* - Events are extended with a function `event.stopPropagation()` to stop
* propagation to parent elements.
* - An option `preventDefault` to stop all default browser behavior.
*
* Usage:
* var hammer = propagatingHammer(new Hammer(element));
* var hammer = propagatingHammer(new Hammer(element), {preventDefault: true});
*
* @param {Hammer.Manager} hammer An hammer instance.
* @param {Object} [options] Available options:
* - `preventDefault: true | false | 'mouse' | 'touch' | 'pen'`.
* Enforce preventing the default browser behavior.
* Cannot be set to `false`.
* @return {Hammer.Manager} Returns the same hammer instance with extended
* functionality
*/
return function propagating(hammer, options) {
var _options = options || {
preventDefault: false
};
if (hammer.Manager) {
// This looks like the Hammer constructor.
// Overload the constructors with our own.
var Hammer = hammer;
var PropagatingHammer = function(element, options) {
var o = Object.create(_options);
if (options) Hammer.assign(o, options);
return propagating(new Hammer(element, o), o);
};
Hammer.assign(PropagatingHammer, Hammer);
PropagatingHammer.Manager = function (element, options) {
var o = Object.create(_options);
if (options) Hammer.assign(o, options);
return propagating(new Hammer.Manager(element, o), o);
};
return PropagatingHammer;
}
// create a wrapper object which will override the functions
// `on`, `off`, `destroy`, and `emit` of the hammer instance
var wrapper = Object.create(hammer);
// attach to DOM element
var element = hammer.element;
if(!element.hammer) element.hammer = [];
element.hammer.push(wrapper);
// register an event to catch the start of a gesture and store the
// target in a singleton
hammer.on('hammer.input', function (event) {
if (_options.preventDefault === true || (_options.preventDefault === event.pointerType)) {
event.preventDefault();
}
if (event.isFirst) {
_firstTarget = event.target;
}
});
/** @type {Object.<String, Array.<function>>} */
wrapper._handlers = {};
/**
* Register a handler for one or multiple events
* @param {String} events A space separated string with events
* @param {function} handler A callback function, called as handler(event)
* @returns {Hammer.Manager} Returns the hammer instance
*/
wrapper.on = function (events, handler) {
// register the handler
split(events).forEach(function (event) {
var _handlers = wrapper._handlers[event];
if (!_handlers) {
wrapper._handlers[event] = _handlers = [];
// register the static, propagated handler
hammer.on(event, propagatedHandler);
}
_handlers.push(handler);
});
return wrapper;
};
/**
* Unregister a handler for one or multiple events
* @param {String} events A space separated string with events
* @param {function} [handler] Optional. The registered handler. If not
* provided, all handlers for given events
* are removed.
* @returns {Hammer.Manager} Returns the hammer instance
*/
wrapper.off = function (events, handler) {
// unregister the handler
split(events).forEach(function (event) {
var _handlers = wrapper._handlers[event];
if (_handlers) {
_handlers = handler ? _handlers.filter(function (h) {
return h !== handler;
}) : [];
if (_handlers.length > 0) {
wrapper._handlers[event] = _handlers;
}
else {
// remove static, propagated handler
hammer.off(event, propagatedHandler);
delete wrapper._handlers[event];
}
}
});
return wrapper;
};
/**
* Emit to the event listeners
* @param {string} eventType
* @param {Event} event
*/
wrapper.emit = function(eventType, event) {
_firstTarget = event.target;
hammer.emit(eventType, event);
};
wrapper.destroy = function () {
// Detach from DOM element
var hammers = hammer.element.hammer;
var idx = hammers.indexOf(wrapper);
if(idx !== -1) hammers.splice(idx,1);
if(!hammers.length) delete hammer.element.hammer;
// clear all handlers
wrapper._handlers = {};
// call original hammer destroy
hammer.destroy();
};
// split a string with space separated words
function split(events) {
return events.match(/[^ ]+/g);
}
/**
* A static event handler, applying event propagation.
* @param {Object} event
*/
function propagatedHandler(event) {
// let only a single hammer instance handle this event
if (event.type !== 'hammer.input') {
// it is possible that the same srcEvent is used with multiple hammer events,
// we keep track on which events are handled in an object _handled
if (!event.srcEvent._handled) {
event.srcEvent._handled = {};
}
if (event.srcEvent._handled[event.type]) {
return;
}
else {
event.srcEvent._handled[event.type] = true;
}
}
// attach a stopPropagation function to the event
var stopped = false;
event.stopPropagation = function () {
stopped = true;
};
//wrap the srcEvent's stopPropagation to also stop hammer propagation:
var srcStop = event.srcEvent.stopPropagation.bind(event.srcEvent);
if(typeof srcStop == "function") {
event.srcEvent.stopPropagation = function(){
srcStop();
event.stopPropagation();
}
}
// attach firstTarget property to the event
event.firstTarget = _firstTarget;
// propagate over all elements (until stopped)
var elem = _firstTarget;
while (elem && !stopped) {
var elemHammer = elem.hammer;
if(elemHammer){
var _handlers;
for(var k = 0; k < elemHammer.length; k++){
_handlers = elemHammer[k]._handlers[event.type];
if(_handlers) for (var i = 0; i < _handlers.length && !stopped; i++) {
_handlers[i](event);
}
}
}
elem = elem.parentNode;
}
}
return wrapper;
};
}));