Is the `ng-model` for the AngularStrap `bs-typeahead` component not accessible in the current scope?

Question

Is the `ng-model` for the AngularStrap `bs-typeahead` component not accessible in the current scope?

I am encountering a problem with the ng-model value in an element that uses AngularStrap's bs-typeahead. It seems to not be accessible within the scope, but it works fine when accessed using {{ var }} in the HTML.

Here is the HTML code:

<input type="text" placeholder="add a destination" ng-options="item as item for item in modelTypeahead" ng-model="selectedDestination" bs-typeahead data-template="templates/SrcDstTypeaheadTemplate.html">

I set the initial value for the variable in my controller:

$scope.selectedDestination = "";

When I place {{ selectedDestination }} elsewhere in the HTML, it displays as expected.

However, if I

console.log($scope.selectedDestination);

in my controller, it shows an empty string.

If I change the initialization to something like:

$scope.selectedDestination = "abc123";

... both the <input> field and the {{ selectedDestination }} display the updated value. The console.log also shows the correct value. However, if I update the typeahead, the {{ selectDestination }} updates but the console.log still shows 'abc123'.

Could there be a scope issue that I am overlooking? I am confused as to why {{ selectedDestination }} displays correctly but the console.log shows something different. It almost seems like the binding is one-way, even though AngularStrap's bs-typeahead should be two-way based on the examples.

javascript angularjs angular-ui angular-strap

Answer 1

Answer №1

Can you clarify where you are using console.log? In order for the value to display, you need to ensure that it has been updated. You can achieve this by implementing the following code:

$scope.watch('selectedDestination', function() { 
    console.log($scope.selectedDestination); 
});

Answer 2

Can you clarify where you are using console.log? In order for the value to display, you need to ensure that it has been updated. You can achieve this by implementing the following code:

$scope.watch('selectedDestination', function() { 
    console.log($scope.selectedDestination); 
});

Answer 3

Answer №2

Have you encountered any lingering issues with this problem? I recently came across a solution to the same issue, which seems to be related to a scope problem or a failure to apply within AngularStrap components. However, pinpointing the exact issue could be a challenge.

While I may not have the expertise to explain the technical reasons behind its efficacy, here is a workaround that you can try:

(1) Transform the variable into an object.

By placing the model and watch on an object instead of a top-level variable, it tends to function better through various layers of directives. The exact rationale behind this phenomenon remains unclear.

(2) Implement a deep watch on the newly created object.

Switching to an object necessitates employing a deep watch on the variable to ensure that any changes are detected by $apply and $digest. This is crucial because, by default, the value will be evaluated for "reference" equality rather than "value" equality. This approach breaks down because the object's "reference" remains the same, only its values change. However, exercise caution with deep comparison due to potential performance implications.

For instance, here's how you can apply this with AngularStrap's typeahead feature:

$scope.selectedDestination = {};

~~~

<input type="text" placeholder="add a destination" ng-options="item as item for item in modelTypeahead" ng-model="selectedDestination.destination" bs-typeahead data-template="templates/SrcDstTypeaheadTemplate.html">

~~~

$scope.$watch('selectedDestination', function(value) {
  console.log('selectedDestination', $scope.subComponent);
}, true); //enabling deep watch is essential here

EDIT Upon further investigation, I encountered some issues linked to the $render function. I will continue to explore this. Best of luck!

Answer 4

Have you encountered any lingering issues with this problem? I recently came across a solution to the same issue, which seems to be related to a scope problem or a failure to apply within AngularStrap components. However, pinpointing the exact issue could be a challenge.

While I may not have the expertise to explain the technical reasons behind its efficacy, here is a workaround that you can try:

(1) Transform the variable into an object.

By placing the model and watch on an object instead of a top-level variable, it tends to function better through various layers of directives. The exact rationale behind this phenomenon remains unclear.

(2) Implement a deep watch on the newly created object.

Switching to an object necessitates employing a deep watch on the variable to ensure that any changes are detected by $apply and $digest. This is crucial because, by default, the value will be evaluated for "reference" equality rather than "value" equality. This approach breaks down because the object's "reference" remains the same, only its values change. However, exercise caution with deep comparison due to potential performance implications.

For instance, here's how you can apply this with AngularStrap's typeahead feature:

$scope.selectedDestination = {};

~~~

<input type="text" placeholder="add a destination" ng-options="item as item for item in modelTypeahead" ng-model="selectedDestination.destination" bs-typeahead data-template="templates/SrcDstTypeaheadTemplate.html">

~~~

$scope.$watch('selectedDestination', function(value) {
  console.log('selectedDestination', $scope.subComponent);
}, true); //enabling deep watch is essential here

EDIT Upon further investigation, I encountered some issues linked to the $render function. I will continue to explore this. Best of luck!

Is the `ng-model` for the AngularStrap `bs-typeahead` component not accessible in the current scope?

Answer №1

Answer №2

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