Concealing the parent element within the DOM if its children have no content

Question

Concealing the parent element within the DOM if its children have no content

<div>
  <h1>Birds</h1>
  <ul>
    <li ng-if="bird.type === 'bird'"
        ng-repeat="bird in creatures">{{bird.name}}</li>
  </ul>
</div>

I received data from the server and I need to display it in the list. However, if the list is empty, I want to hide the entire div container. For instance, if bird.type === 'bird' is not present in the array, I want the div to be hidden. I can't use ng-if="bird.type === 'bird'" directly on the div because I need to access the bird object after the ng-repeat. Is there a way to check if the li is empty and then hide the div?

Check out this Plunkr example

AngularJS ng-repeat handle empty list case - Although similar, this is not exactly what I am looking for. I don't want to hide the li if it's empty, but rather hide the parent div that contains the h1 when the li is empty.

javascript angularjs

Answer 1

Answer №1

If you want to display a list of birds, you can use the following code:

<div ng-if="hasBirds(creatures)">
  <h1>Birds</h1>
  <ul>
    <li ng-if="bird.type === 'bird'"
        ng-repeat="bird in creatures">{{bird.name}}</li>
  </ul>
</div>

To make this work, you need to add the hasBirds function to your controller or directive.

$scope.hasBirds = function(list){
    return list.filter(function(item){return item.type === 'bird'}).length > 0;
}

By using the hasBirds function, you can easily show or hide the heading based on whether there are any birds in the list.

Answer 2

If you want to display a list of birds, you can use the following code:

<div ng-if="hasBirds(creatures)">
  <h1>Birds</h1>
  <ul>
    <li ng-if="bird.type === 'bird'"
        ng-repeat="bird in creatures">{{bird.name}}</li>
  </ul>
</div>

To make this work, you need to add the hasBirds function to your controller or directive.

$scope.hasBirds = function(list){
    return list.filter(function(item){return item.type === 'bird'}).length > 0;
}

By using the hasBirds function, you can easily show or hide the heading based on whether there are any birds in the list.

Answer 3

Answer №2

If you're looking for a better approach in the given scenario, my suggestion would be to implement a filter instead of resorting to "ng-if". You can create a custom filter like this:

angular.module('moduleName').filter(birdsFilter);
function birdsFilter(creature) {
    return creature.type == 'bird';
}

This filter can then be utilized to refactor your code as shown below:

<div ng-hide="birds.length">
  <h1>Birds</h1>
  <ul>
    <li ng-repeat="bird in birds = (creatures | filter:birdsFilter)">{{bird.name}}</li>
  </ul>
</div>

Answer 4

If you're looking for a better approach in the given scenario, my suggestion would be to implement a filter instead of resorting to "ng-if". You can create a custom filter like this:

angular.module('moduleName').filter(birdsFilter);
function birdsFilter(creature) {
    return creature.type == 'bird';
}

This filter can then be utilized to refactor your code as shown below:

<div ng-hide="birds.length">
  <h1>Birds</h1>
  <ul>
    <li ng-repeat="bird in birds = (creatures | filter:birdsFilter)">{{bird.name}}</li>
  </ul>
</div>

Answer 5

Answer №3

In my opinion, there are multiple viable solutions provided here. However, none of them are fully optimized. My suggestion would be to filter the data in your controller or postlink function.

$scope.animals = {
    dogs: $scope.creates.filter(function(a){return a.type == 'dog'}),
    cats: $scope.creates.filter(function(a){return a.type == 'cat'}),
    birds: $scope.creates.filter(function(a){return a.type == 'bird'}),
    fishes: $scope.creates.filter(function(a){return a.type == 'fish'})
};

By doing this, you will only need to process the array of creatures once, in one location. This eliminates the need for the digest cycle to constantly reassess the array for DOM updates. Your markup would then look like this:

<div ng-if="animals.birds.length">
  <h1>Birds</h1>
  <ul>
    <li ng-repeat="bird in animals.birds">{{bird.name}}</li>
  </ul>
</div>

Answer 6

In my opinion, there are multiple viable solutions provided here. However, none of them are fully optimized. My suggestion would be to filter the data in your controller or postlink function.

$scope.animals = {
    dogs: $scope.creates.filter(function(a){return a.type == 'dog'}),
    cats: $scope.creates.filter(function(a){return a.type == 'cat'}),
    birds: $scope.creates.filter(function(a){return a.type == 'bird'}),
    fishes: $scope.creates.filter(function(a){return a.type == 'fish'})
};

By doing this, you will only need to process the array of creatures once, in one location. This eliminates the need for the digest cycle to constantly reassess the array for DOM updates. Your markup would then look like this:

<div ng-if="animals.birds.length">
  <h1>Birds</h1>
  <ul>
    <li ng-repeat="bird in animals.birds">{{bird.name}}</li>
  </ul>
</div>

Answer 7

Answer №4

To display only bird-related items from a list, filter the items based on their type and store the filtered items in a designated scope property. You can then use this property to control the visibility of the corresponding elements.

<div ng-show="birds.length">
  <h1>Birds</h1>
  <ul>
    <li ng-repeat="bird in creatures | filter:birdType as birds">{{bird.name}}    </li>
  </ul>
</div>

Next, define the birdType filter function in your controller:

$scope.birdType = function(creature) {
    return creature.type === 'bird';
};

Answer 8

To display only bird-related items from a list, filter the items based on their type and store the filtered items in a designated scope property. You can then use this property to control the visibility of the corresponding elements.

<div ng-show="birds.length">
  <h1>Birds</h1>
  <ul>
    <li ng-repeat="bird in creatures | filter:birdType as birds">{{bird.name}}    </li>
  </ul>
</div>

Next, define the birdType filter function in your controller:

$scope.birdType = function(creature) {
    return creature.type === 'bird';
};

Answer 9

Answer №5

Utilizing the ng-show="cats.length" attribute to hide div elements when the length is zero.

Performing inline filtering based on object properties such as

cat in creatures | filter:{type: 'cat'} as cats

as explained in this Stack Overflow post.

EXAMPLE IN ACTION:

var app = angular.module('App', []);
app.filter(birdsFilter);
function birdsFilter(creature) {
    return creature.type == 'bird';
}
app.controller('Ctrl', function($scope) {
  $scope.creatures = [
      {
        name : 'Cho-cho',
        type : 'bird'
      },
      {
        name : 'Floo-floo',
        type : 'dog'
      },
            {
        name : 'Pou-pou',
        type : 'bird'
      },
      {
        name : 'Oop-flup',
        type : 'bird'
      },
            {
        name : 'Chio-mio',
        type : 'cat'
      },
      {
        name : 'Floo-floo',
        type : 'dog'
      },
            {
        name : 'Loo-Li',
        type : 'dog'
      },
      {
        name : 'Pops-Mops',
        type : 'bird'
      },
            {
        name : 'Boo-Moo',
        type : 'dog'
      },
      {
        name : 'Iop-Pio',
        type : 'dog'
      },
            {
        name : 'Floop-cho',
        type : 'bird'
      }
      
    ]
});

<!DOCTYPE html>
<html ng-app="App">

<head>
  <script data-require="<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="80e1eee7f5ece1f2eaf3c0b1aeb5aeb7">[email protected]</a>" data-semver="1.5.7" src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.7/angular.min.js"></script>
  <link rel="stylesheet" href="style.css" />
  <script src="script.js"></script>
</head>

<body ng-controller="Ctrl">
  <div ng-show="birds.length">
    <h1>Birds</h1>
    <ul>
      <li ng-repeat="bird in creatures | filter:{type: 'bird'} as birds">{{bird.name}} </li>
    </ul>
  </div>
  <div ng-show="dogs.length">
    <h1>Dogs</h1>
    <ul>
      <li ng-repeat="dog in creatures | filter:{type: 'dog'} as dogs">{{dog.name}} </li>
    </ul>
  </div>
  <div ng-show="cats.length">
    <h1>Cats</h1>
    <ul>
      <li ng-repeat="cat in creatures | filter:{type: 'cat'} as cats">{{cat.name}} </li>
    </ul>
  </div>
  <div ng-show="fishes.length">
    <h1>Fish</h1>
    <ul>
      <li ng-repeat="fish in creatures | filter:{type: 'fish'} as fishes">{{fish.name}} </li>
    </ul>
  </div>

</body>

</html>

Answer 10

Utilizing the ng-show="cats.length" attribute to hide div elements when the length is zero.

Performing inline filtering based on object properties such as

cat in creatures | filter:{type: 'cat'} as cats

as explained in this Stack Overflow post.

EXAMPLE IN ACTION:

var app = angular.module('App', []);
app.filter(birdsFilter);
function birdsFilter(creature) {
    return creature.type == 'bird';
}
app.controller('Ctrl', function($scope) {
  $scope.creatures = [
      {
        name : 'Cho-cho',
        type : 'bird'
      },
      {
        name : 'Floo-floo',
        type : 'dog'
      },
            {
        name : 'Pou-pou',
        type : 'bird'
      },
      {
        name : 'Oop-flup',
        type : 'bird'
      },
            {
        name : 'Chio-mio',
        type : 'cat'
      },
      {
        name : 'Floo-floo',
        type : 'dog'
      },
            {
        name : 'Loo-Li',
        type : 'dog'
      },
      {
        name : 'Pops-Mops',
        type : 'bird'
      },
            {
        name : 'Boo-Moo',
        type : 'dog'
      },
      {
        name : 'Iop-Pio',
        type : 'dog'
      },
            {
        name : 'Floop-cho',
        type : 'bird'
      }
      
    ]
});

<!DOCTYPE html>
<html ng-app="App">

<head>
  <script data-require="<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="80e1eee7f5ece1f2eaf3c0b1aeb5aeb7">[email protected]</a>" data-semver="1.5.7" src="https://ajax.googleapis.com/ajax/libs/angularjs/1.5.7/angular.min.js"></script>
  <link rel="stylesheet" href="style.css" />
  <script src="script.js"></script>
</head>

<body ng-controller="Ctrl">
  <div ng-show="birds.length">
    <h1>Birds</h1>
    <ul>
      <li ng-repeat="bird in creatures | filter:{type: 'bird'} as birds">{{bird.name}} </li>
    </ul>
  </div>
  <div ng-show="dogs.length">
    <h1>Dogs</h1>
    <ul>
      <li ng-repeat="dog in creatures | filter:{type: 'dog'} as dogs">{{dog.name}} </li>
    </ul>
  </div>
  <div ng-show="cats.length">
    <h1>Cats</h1>
    <ul>
      <li ng-repeat="cat in creatures | filter:{type: 'cat'} as cats">{{cat.name}} </li>
    </ul>
  </div>
  <div ng-show="fishes.length">
    <h1>Fish</h1>
    <ul>
      <li ng-repeat="fish in creatures | filter:{type: 'fish'} as fishes">{{fish.name}} </li>
    </ul>
  </div>

</body>

</html>

Concealing the parent element within the DOM if its children have no content

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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