mohsen-angular-leaflet-directive/src/services/leafletWatchHelpers.js

angular-leaflet-directive - An AngularJS directive to easily interact with Leaflet maps

angular.module('leaflet-directive')
.service('leafletWatchHelpers', function() {

  var _maybe = function(scope, watchFunctionName, thingToWatchStr, watchOptions, initCb) {
    //watchOptions.isDeep is/should be ignored in $watchCollection
    var unWatch = scope[watchFunctionName](thingToWatchStr, function(newValue, oldValue) {
      initCb(newValue, oldValue);
      if (!watchOptions.doWatch) {
        unWatch();
      }
    }, watchOptions.isDeep);

    return unWatch;
  };

  /*
  @name: maybeWatch
  @description: Utility to watch something once or forever.
  @returns unWatch function
  @param watchOptions - see markersWatchOptions and or derrivatives. This object is used
  to set watching to once and its watch depth.
  */
  var _maybeWatch = function(scope, thingToWatchStr, watchOptions, initCb) {
    return _maybe(scope, '$watch', thingToWatchStr, watchOptions, initCb);
  };

  /*
  @name: _maybeWatchCollection
  @description: Utility to watch something once or forever.
  @returns unWatch function
  @param watchOptions - see markersWatchOptions and or derrivatives. This object is used
  to set watching to once and its watch depth.
  */
  var _maybeWatchCollection = function(scope, thingToWatchStr, watchOptions, initCb) {
    return _maybe(scope, '$watchCollection', thingToWatchStr, watchOptions, initCb);
  };

  return {
    maybeWatch: _maybeWatch,
    maybeWatchCollection: _maybeWatchCollection,
  };
});