angularjs $watch cannot detect change of Property in an object

Question

I'm setting watch for $scope object will not trigger $watch change event unless the whole value is changed

Example :

//Some where in .run function i set rootScope and set $watch too.
$rootScope.config = {date:'11/4/2015',moreValues:'etc'};

//setting $watch
$rootScope.$watch('config',function(new,old) {
console.log('config value changed :)',new);
});

//----->Inside Controller----------

//NOw THIS WILL NOT TRIGGER $watch
$rootScope.config.date = 'another day';

//Same as this, it will also not trigger $watch
var temp = $rootScope.config;
temp.date = 'another day';
$rootScope.config = temp;

//YET THIS WILL WORK JUST FINE :) AND WILL TRIGGER $watch
var temp = angular.copy($rootScope.config);
temp.date = 'another day';
$rootScope.config = temp;

can someone tell me why is this behavior? is there a better way to trigger $watch on change of object Property?

Arun P Johny · Accepted Answer · 2015-05-12 02:49:08Z

5

You can use $watchCollection, or pass a third param as true

$rootScope.$watch('config',function(value,old) {
console.log('config value changed :)',value);
}, true);

or

$rootScope.$watchCollection('config',function(value,old) {
console.log('config value changed :)',value);
});

Scope $watch() vs. $watchCollection() In AngularJS

edited May 12, 2015 at 2:49

answered May 12, 2015 at 1:30

Arun P Johny

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