javascript - 当一个值改变时如何改变另一个值

Question

我有例如这样的代码:

scope.people;
scope.agedPeople;

如果人们重视改变，我需要这样做:

scope.agedPeople = scope.people * 0.3;

如果gedPeople 值发生变化，我需要这样做:

scope.people = scope.agedPeople / 0.3;

我想使用 $watch，但正如你所看到的，我有循环引用......我这样解决了它:

    scope.checkIsPeopleCounted = function() {
      var countedPeople;

      countedPeople = scope.agedPeople * 0.3;

      return countedPeople === scope.people;
    };


    scope.checkIsAgedPeopleCounted = function() {
      var countedAgedPeople;

      countedAgedPeople = scope.people / 0.3;

      return countedAgedPeople === scope.agedPeople;
    };

    scope.$watch('people', function() {
      !scope.checkIsAgedPeopleCounted() && (scope.agedPeople = scope.people / 0.3);
    });

scope.$watch('agedPeople', function() {
  !scope.checkIsPeopleCounted() && (scope.people = scope.agedPeople * 0.3);
});

不过看起来不太好。也许还有另一种解决方案？

如何将其做成 Angular ？

Answer 1

如果没有更多信息，这有点困难。但理论上你可以像这样观察范围内的值:

$scope.$watch('agedPeople', function(newValue, oldValue){});

请参阅 Scope 文档。$watch: Angular Scope.$watch documentation .

但在你的情况下，你有一个循环引用。您可以通过向返回结果的范围添加方法来解决此问题。

var MULTIPLIER = .3;
$scope.agedPeople = 1;
$scope.people = 1;

$scope.getAgedPeople = function () {
  return $scope.people * MULTIPLIER;
};

$scope.getPeople = function () {
  return $scope.agedPeople * MULTIPLIER;
};

希望对您有所帮助!