angular ng-if or ng-show responds slow (2second delay?)

Question

I'm trying to show or hide a loading indicator on a button when a request is busy. I do that with angular by changing the $scope.loading variable when a request is loading or when it's done loading.

 $scope.login = function(){
     $scope.loading = true;
    apiFactory.getToken()
        .success(function(data){
            
        })
        .error(function(error){
            
        })
         .finally(function(){
               $timeout(function() {
                 $scope.loading = false;
               }, 0);
         });
 };

In the frontend:

<button ng-disabled="loading" class="button button-outline button-positive" type="submit">
Log in 
<span ng-if="loading" class="ion-refreshing"></span>
</button>

This works fine, but the loading icon (ion-refreshing) is shown for about 2 seconds, while the $scope variable is updated immediately. I tried $scope.$apply but that doesn't seem to be what's wrong here, the scope is updated just fine and immediately after the request. It's just the icon that isn't responding quickly enough.

Solution 1

Try removing ngAnimate if you're not using it from your app config and index.html page:

angular.module('myApp', [...'ngAnimate',...])

@Spock; if you still require the use of ngAnimate then leave your app config untouched and just add the following CSS:

.ng-hide.ng-hide-animate{
     display: none !important;
}

That will hide the animated icon straight after your condition is met.

As you can see we are setting .ng-hide-animate to hidden. This is what causes the delay as it waits for the animation to complete. You can add an animation to your hide event as the class name implies instead of hiding it as in the example above.

Solution 2

I had the same issue, and worked-around it by using ng-class with the 'hidden' class name to hide the element instead of using ng-if or ng-show/ng-hide.

Solution 3

I found some solutions here, but the best for me was overriding the styling for the .ng-animate class:

.ng-animate.no-animate {
    transition: 0s none;
    -webkit-transition: 0s none;
    animation: 0s none;
    -webkit-animation: 0s none;
}

In html:

<button ng-disabled="loading" class="button button-outline button-positive" type="submit">
    Log in 
    <span ng-if="loading" class="ion-refreshing no-animate"></span>
</button>

This is an example: http://jsfiddle.net/9krLr/27/

I hope help you.

Solution 4

I was facing a similar issue, I used $scope.$evalAsync() to force update the binding.

It works like a charm.

Avoid using $scope.$apply as it can conflict with an already-running $digest phase.

if(selectedStatistics.length === 0 || selectedWorkgroups.length === 0){
    ctrl.isSaveDisabled = true;
    $scope.$evalAsync();
} else{
    ctrl.isSaveDisabled = false;
    $scope.$evalAsync();
}

Solution 5

I had the same issue when using

<div *ngIf='shouldShow'>
    <!-- Rest of DIV content here -->
</div>

In my case I solved it by adding a class:

.hidden {
  display: none;
}

and then adding the class conditionally instead of using *ngIf:

<div [ngClass]="{'hidden': !shouldShow}">
    <!-- Rest of DIV content here -->
</div>

If always using it this way, I would consider renaming shouldShow to shouldHide (and negate the logic that assigns it), so it can be used as shouldHide instead of !shouldShow.

If you have display: flex in your CSS for the DIV's existing class, that display property might take precedence over the display: hidden. An easy fix can be to use display: none !important instead, but there are often better solutions to ensure precedence in other ways. Here is a good read about alternatives.

View more solutions

Comments

[Eamonn Gahan]

I had a simple page with only a couple of ng-if, ng-show that was visibly slow. I removed ngAnimate and it fixed the problem for me. Thanks!

[Clark]

This solved a problem I was having as well... Do you know why the presence of ngAnimate was causing the slow transition?

[Thiago Festa]

Seems related with animations and/or event handlers. Not really sure why the others are slow, but I'd like to know

[Spock]

Had the same problem - removing ngAnimate solved it.. but this is not good .. many modules need ngAnimate to do cool animations.. what to do? ngAnimattias where are you? :)

[jsmedmar]

how can you do this?

[Joao]

In the case of ng-if, adding just .ng-leave { display:none; } to the element did the trick for me (!important wasn't needed).

[Aron]

This is so much faster! Why is this??

[John Rix]

I would think this is simply down to the fact that using ngAnimate applies entry/exit animation behaviours to elements using ng-if/ng-show, while it does not do so for changes in ng-class expressions.

[Sarah Tammam]

Worked for me. But does it have any disadvantages?

[pixlboy]

I haven't encountered any. Its very handy in case of async operations.

[Sarah Tammam]

Thank you for the helpful reply :)

[Chris22]

@neimad how is this done? In my case, I need to use ng-if to test whether a property value is null (which it is for a couple seconds waiting for the api call), so two select elements are showing briefly. So are you not using ng-if at all? Thanks.

[Abdeali Chandanwala]

By the way this delayed issue is mainly happening in the localhost environment and rarely in production - dont know why