AngularJS: ng-if not working in combination with ng-click?
Solution 1:
- Why does 1 not work?: Because an ngIf defines its own scope, which prototypically inherits from its parent scope (just like ngRepeat). So, when you change the value of a field inside an ngIf, you change it in the ngIf scope, and not in its parent scope.
- Should 1 work?: No
- Why does 2 work?: Because in that case you modify the content of an object which is referenced by the ngId scope, through inheritance.
- Should 2 work?: Yes
- Can I rely 2 to work in future updates of AngularJS?: Why shouldn't you?
This scope inheritance mechanism is explained very well in https://github.com/angular/angular.js/wiki/Understanding-Scopes
Solution 2:
Since ngIf
creates own scope, to make it work you can define toggle1
in one scope:
JS**
$scope.toggleMe = function(){
$scope.toggle1 = !$scope.toggle1;
}
HTML
<li ng-init="toggle1 = true">
ng-if toggle1: {{ toggle1 }}
<p>
<button ng-if="toggle1" ng-click="toggleMe()">Turn On</button>
<button ng-if="!toggle1" ng-click="toggleMe()">Turn Off</button>
does not work
</li>
See Demo Plunker
Solution 3:
1. Why does 1 not work?ng-if
creates a new scope. which causes the "weird" binding behavior as explained in this video: http://egghead.io/lessons/angularjs-the-dot
2. Should 1 work?
Reading properties from the parent scope works (prototype chain), but writing to the scope creates a new property on the child scope. Creating a disconnected
3. Why does 2 work?
The same property is read from the parent scope (obj). The write in ng-click changes the "obj" object, not the scope.
4/5. Should 2 work? Can I rely 2 to work in future updates of AngularJS?
YES, this is the documented expected behavior.
Tip: I use the Chrome extension AngularJS Batarang to gain insights about which variables are on which scope.