Checking if object is empty, works with ng-show but not from controller? - angularjs

Question

I have a JS object declared like so
$scope.items = {};
I also have a $http request that fills this object with items. I would like to detect if this item is empty, it appears that ng-show supports this... I enter
ng-show="items"
and magically it works,I would also like to do the same from a controller but i can't seem to get it to work, it appears I may have to iterate over the object to see if it has any properties or use lodash or underscore.
Is there an alternative?
I did try
alert($scope.items == true);
but it always returns false , when the object is created and when populated with $http, so its not working that way.

Answer 1

Or you could keep it simple by doing something like this:
alert(angular.equals({}, $scope.items));

Answer 2

In a private project a wrote this filter
angular.module('myApp')
.filter('isEmpty', function () {
var bar;
return function (obj) {
for (bar in obj) {
if (obj.hasOwnProperty(bar)) {
return false;
}
}
return true;
};
});
usage:
<p ng-hide="items | isEmpty">Some Content</p>
testing:
describe('Filter: isEmpty', function () {
// load the filter's module
beforeEach(module('myApp'));
// initialize a new instance of the filter before each test
var isEmpty;
beforeEach(inject(function ($filter) {
isEmpty = $filter('isEmpty');
}));
it('should return the input prefixed with "isEmpty filter:"', function () {
expect(isEmpty({})).toBe(true);
expect(isEmpty({foo: "bar"})).toBe(false);
});
});
regards.

Answer 3

Use an empty object literal isn't necessary here, you can use null or undefined:
$scope.items = null;
In this way, ng-show should keep working, and in your controller you can just do:
if ($scope.items) {
// items have value
} else {
// items is still null
}
And in your $http callbacks, you do the following:
$http.get(..., function(data) {
$scope.items = {
data: data,
// other stuff
};
});

Answer 4

another simple one-liner:
var ob = {};
Object.keys(ob).length // 0

Answer 5

If you couldn't have the items OBJ equal to null, you can do this:
$scope.isEmpty = function (obj) {
for (var i in obj) if (obj.hasOwnProperty(i)) return false;
return true;
};
and in the view you can do:
<div ng-show="isEmpty(items)"></div>
You can do
var ob = {};
Object.keys(ob).length
Only if your browser supports ECMAScript 5. For Example, IE 8 doesn't support this feature.
See http://kangax.github.io/compat-table/es5/ for more infos

Answer 6

if( obj[0] )
a cleaner version of this might be:
if( typeof Object.keys(obj)[0] === 'undefined' )
where the result will be undefined if no object property is set.

Answer 7

Or, if using lo-dash: _.empty(value).
"Checks if value is empty. Arrays, strings, or arguments objects with a length of 0 and objects with no own enumerable properties are considered "empty"."

Answer 8

Check Empty object
$scope.isValid = function(value) {
return !value
}

Answer 9

you can check length of items
ng-show="items.length"