可以't从一个角度内更新全局变量.forEach循环

Can't update a global variable from within an angular.forEach loop

本文关键字：一个 更新 循环 forEach 全局变量 可以      更新时间：2023-09-26

在尝试从Angular.forEach循环中修改全局变量时，我似乎陷入了困境。

我可以很好地修改变量，但当在循环之外访问时，似乎无法将更改应用于变量。

我尝试了各种各样的"var self=this"，并在整个循环中使用"this.addres=[]"来访问数组，但这也导致了同样的问题。当我到达我的"return"语句时，我的更改已经丢失。

这是代码：

$scope.getLocation = function(val) {
var geocoderRequest = {
    address: String(val),
    componentRestrictions: {
        'country': 'US'
    }
};
var addresses = [1]; // **** shows addresses as [1] *****
geocoder.geocode(geocoderRequest, function(callbackResult) {
    console.log('address in geocode: ' + addresses); // ***** shows addresses as [1] ****
    var f = '';
    angular.forEach(callbackResult.results, function(item) {
        console.log('address in angular: ' + addresses); // **** shows addresses as [1] *****
        if (item.types[0] == 'locality') {
            for (f = 1; f < item.address_components.length; f++) {
                if (item.address_components[f].types[0] ==
                    "administrative_area_level_1") {
                    addresses.push(item.address_components[0].short_name + ', ' + item.address_components[
                        f].short_name);
                    console.log('addresses in each: ' + addresses); // **** shows addresses as [1, 2, 3] after I 'push' 2 and 3 into addresses array ****
                    break;
                }
            }
        }
    });
});
console.log('addresses outside: ' + addresses); // ***** shows addresses as [1] even after pushing 2 and 3 *****
return addresses;

}；

最终的解决方案是使用Angular的$q返回一个promise：

在控制器中：

.controller('LaunchformController', 
['$scope', '$q', 'geocoder', function ($scope, $q, geocoder) {
  $scope.getLocation = function(val) {      
    var deferred = $q.defer();      
    geocoder.geocode({ address: String(val), componentRestrictions: {'country':'US'} }, 
      function(callbackResult) {        
        deferred.resolve(callbackResult);
    });
    return deferred.promise;            
  };
}])

在服务中：

.service('geocoder',function() {
    this.geocode=function(georequest, outerCallback) {
      var geocoder = new google.maps.Geocoder();
      geocoder.geocode( georequest, function(results, status) {        
        if (status == google.maps.GeocoderStatus.OK) {          
          var f = '';                  
          var addresses = [];
          angular.forEach(results, function(item){  
            if (item.types[0] == 'locality') {          
              for (f=1;f<item.address_components.length;f++) {              
                if (item.address_components[f].types[0] == "administrative_area_level_1") {
                addresses.push(item.address_components[0].short_name + ', ' + item.address_components[f].short_name);            
                break;
                }
              }
            }            
          });
          outerCallback(addresses);         
        } else {
          outerCallback({success:false, err: new Error('Geocode was not successful for the following reason: ' + status), results: null});
        }
      });
    };
  })
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