tchen-vuelayers/lib/rx-ext/from-ol-event.js

Web map Vue components with the power of OpenLayers

/**
 * VueLayers
 * Web map Vue components with the power of OpenLayers
 *
 * @package vuelayers
 * @author Vladimir Vershinin <ghettovoice@gmail.com>
 * @version 0.11.1
 * @license MIT
 * @copyright (c) 2017-2019, Vladimir Vershinin <ghettovoice@gmail.com>
 */
import _typeof from '@babel/runtime-corejs2/helpers/esm/typeof';
import _toConsumableArray from '@babel/runtime-corejs2/helpers/esm/toConsumableArray';
import _Array$isArray from '@babel/runtime-corejs2/core-js/array/is-array';
import { fromEventPattern } from 'rxjs/_esm5/internal/observable/fromEventPattern';
import { merge } from 'rxjs/_esm5/internal/observable/merge';

/**
 * Creates an Observable using OpenLayers event pattern that emits events coming from the given event target.
 *
 * @example **Subscribe on view center change events**
 * const map = ol.Map({ ... })
 * const changes = Observable.fromOlEvent(map.getView(), 'change:center')
 *
 * changes.subscribe(({ coordinate }) => console.log(coordinate))
 *
 * @param {ol.Object} target OpenLayers event target.
 * @param {string|Object[]} eventName The event name of interest, being emitted by the `target`
 *                          or an array of events/selectors like `[{ event: 'event1', selector?: x => x }, ...]`.
 * @param {function(...*): *} [selector] An optional function to post-process results. It takes the arguments
 *    from the event handler and should return a single value.
 * @return {Observable<T>}
 * @memberOf {Observable}
 */

function fromOlEvent(target, eventName, selector) {
  if (_Array$isArray(eventName)) {
    return merge.apply(void 0, _toConsumableArray(eventName.map(function (elem) {
      var eventName, selector;

      if (_typeof(elem) === 'object') {
        eventName = elem.event;
        selector = elem.selector;
      } else {
        eventName = elem;
      }

      return fromOlEvent(target, eventName, selector);
    })));
  }

  return fromEventPattern(function (handler) {
    return target.on(eventName, handler);
  }, function (handler) {
    return target.un(eventName, handler);
  }, selector);
}

export default fromOlEvent;