angular.js - angularJs的$scope

Question

(1) Two variables are defined in the controller

$scope.a="aaaaa";
$scope.b="bbbbb";

(2) Also define an object to save

$scope.object={
    arr:[$scope.a,$scope.b]
}

(3) Now dynamically modify the values ​​of $scope.a and $scope.b.
But the value in $scope.object.arr has not changed. Why is this? Shouldn't it be updated in real time?

Answer 1

Because a和b都是原始数据类型，在声明object的时候，向arr里填入的就是a和b corresponds to the string itself

So when you modify it later $scope.a和$scope.b时，$scope.object it doesn’t change along with it.

This is like, I have two apples, gave you one, and then I took a bite of mine, because the apples look exactly the same (assuming, it is a false proposition), so I expect that the apple in your hand will also appear A bitten gap.

Answer 2

You can use $watch

$scope.$watch('a',function(v){
    $scope.object.arr
});
$scope.$watch('b',function(v){
    $scope.object.arr[1] = v;
});

Answer 3

The default is shallow traversal

Answer 4

$scope.a, $scope.b are strings, and assignment is equivalent to directly assigning strings to arrays.
If you want to achieve your goal, you can monitor a and b. When a and b change, assign a value to the object.