I have the following variable:
var $scope.abc = [{"a":22,"b":"x"},{"a":33,"b":"y"}];
Is it possible to do a watch on this and watch for just the value of the field a changing?
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1 Answer
Is it possible to do a watch on this and watch for just the value of the field a changing
Sure.
If you want to watch only for value a you can define ng-change for (suppose a is a input) input a.
HTML
<div ng-controller="Controller">
<div ng-repeat="val in abc">
<input type='text' ng-model='val.a' ng-change="onAChange(val.a)">
<input type='text' ng-model='val.b'>
</div>
</div>
JS
$scope.onAChange = function(mod){
console.log(mod);
};
Demo 1 Plunker
Other way, to $watch on all object abc and write "deep" watch, something like:
$scope.$watch(function () {
return $scope.abc[0].a;
},
function (newValue, oldValue) {
if(newValue == oldValue){return;}
console.log(newValue, oldValue);
}, true);
Demo 2 Plunker
As a side note:
You don't need var before $scope.abc.
1 Comment
Alan2
Thanks for the comment about var. I will remove that, I was just trying to give an example and made a mistake. Can you explain a bit more about ng-change. I have never used that. Also I am not really sure how to code the .$watch. Thanks
