Adding filter to ng-repeat - angularjs

Question

I'm currently making a front-end with Angular.
I have a JSON file like following:
{
"groups": [
group1: {
"part":1
},
group2: {
"part":2
}
]
}
And I have lists like following:
<li ng-class="{active: section >= {{group.number}}}" ng-bind="group.title" ng-repeat="group in groups" ></li>
Let's say there are 100 groups in my JSON file. If I want to only show groups with "part":1, how do I add this filter in ng-repeat?

Answer 1

You can pass an object to filter with the key/value you want to filter on:
ng-repeat="group in groups | filter:{part:1}"

Answer 2

try this
ng-repeat="group in groups | filter:{'part': 1}:true"
from official documentation
In HTML Template Binding
{{ filter_expression | filter : expression :
comparator}}
for comparator value if its true
true: A shorthand for function(actual, expected) { return
angular.equals(actual, expected)}. This is essentially strict
comparison of expected and actual.
this gives you the exact match

Answer 3

Consider also passing a function rather than Object into filter (which may work this time, but not all things are easily expressible in a readable fashion directly in the view):
ng-repeat="group in groups | filter:functionOnScope"
The | pipe operates on the thing to the left groups, so filter is a function whose first argument receives groups and whose subsequent arguments appear after the :. You could visualize a | b:c:d | e as e(b(a,c,d)) - once I realized that I used filters more for simple things.
So the second argument filter receives is a predicate (function that takes in something and returns true or false to operate on each element - like a SQL WHERE clause) inside groups. Filters are super useful - if you have quick logic or transformations you want to do in the view (and you don't need to test it) then they can make your controllers and directives more succinct. (So instead of ng-if="collection[collection.length - 1].length > 0" you could write ng-if="collection | last | some", which is much more readable.)
If you have complicated logic, it may be better to put in a controller or directive instead of the view (this is also easier to unit test that way if you care about it) - if it's in the view you need something like PhantomJS at a minimum to emulate the DOM. Assuming you bound some dynamicallySelectedPart on the $scope to 1, 2, etc. maybe as an ng-model on a <select /> so the user can select it, then you can just write this to keep it dynamically up-to-date.
$scope.functionOnScope = function (elementInGroups) {
// Maybe do a check like:
// if ($scope.dynamicallySelectedPart === elementInGroups.part) {
return true;
// }
// Some other logic...
return false;
};

Answer 4

Your JSON looks malformed in that you have an array with key-value pairs.
Below is some code that should work. I am using the Controller ViewAs syntax.
HTML
<div ng-app="MyApp">
<div ng-controller="MyController as me">
{{me.greeting}}
<ul>
<li ng-repeat="group in me.groups | filter:{'part': 1}:true">
{{group}}
</li>
</ul>
</div>
JS
var myApp = angular.module('MyApp',[]);
myApp.controller('MyController', function() {
this.greeting = 'Hola!';
this.groups = [ {id: 'group1', "part":1 }, {id: 'group2', "part":2 } ];
});
Code Pen Here