In my Angular application, I am facing an issue with updating the local scope from within a service. Specifically, I want to replace the array that the scope is pointing at with another array.
Here is the process after clicking an element:
clickDirective () {
restrict: 'A'.
link: function (scope, element, attrs) {
if ($rootScope.hasCertainValue) {
FirstService.handle(scope, valueX)
}
}
}
/* Calls FirstService.handle */
FirstService () {
handle (scope, valueX) {
if (certainCriteriaMet) {
SecondService.handle(scope, valueX)
}
}
}
/* Calls SecondService.handle */
SecondService () {
handle (scope, valueX) {
/* This is where the issue arises */
console.log(scope.value) // prints: ['a']
// Option a)
scope.value = ['a', 'b'] // this is what I want to do
// Option b)
scope.value.push('b') // this is what works
scope.$apply()
// With option a), the UI is not updated
console.log(scope.value) // prints ['a', 'b']
// However, next time this function is called,
// the value of scope.value has switched back to ['a'].
// Option b) updates the UI
console.log(scope.value) // prints ['a', 'b']
// The value remains ['a', 'b'] in future calls.
}
}
Why can't I change the object the scope is pointing at, but I can modify it instead?
The SecondService includes another function called by a different directive using the same scope. In that function, I can achieve the desired operation of replacing the current array with a new one.
I suspect there may be race conditions causing this behavior.
----- Edit -----
I believe I have identified the underlying problem. The scope object in SecondService is merely a reference to the actual scope object.
scope.value ------> [array]
scope.atSecondService --------> scope.value -------> [array]
When I change the array at scope.atSecondService, it results in:
scope.value ------> [array]
scope.atSecondService -----> [newArray] <---/--- scope.value
This still leaves me puzzled about why calling a similar function from another directive works as intended.
----- Edit 2 -----
Alternatively, it could be that the behavior is inconsistent. It appears that a new local level scope is created at the element level instead of accessing the $scope at the controller. Although initially, the scope received seems to be the controller's scope based on its value.
Perhaps someone else has more insight into this issue?