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ng-mouseover and leave to toggle item using mouse in angularjs

Posted by: admin November 7, 2017 Leave a comment

Questions:

HTML:

<ul ng-repeat="task in tasks">
    <li ng-mouseover="hoverIn()" ng-mouseleave="hoverOut()">{{task.name}}</li>
    <span ng-show="hoverEdit"><a>Edit</a></span>
</ul>

JS:

$scope.hoverIn = function(){
    $scope.hoverEdit = true;
};

$scope.hoverOut = function(){
    $scope.hoverEdit = false;
};

The code is ridiculous because I think it’s too much. I think it can be simplified. Anyway the result toggle all the item once it’s hovered. I’ve jQuery background, so I have no idea how to make single item work in ng-repeat.

Answers:

Angular solution

You can fix it like this:

$scope.hoverIn = function(){
    this.hoverEdit = true;
};

$scope.hoverOut = function(){
    this.hoverEdit = false;
};

Inside of ngMouseover (and similar) functions context is a current item scope, so this refers to the current child scope.

Also you need to put ngRepeat on li:

<ul>
    <li ng-repeat="task in tasks" ng-mouseover="hoverIn()" ng-mouseleave="hoverOut()">
        {{task.name}}
        <span ng-show="hoverEdit">
            <a>Edit</a>
        </span>
    </li>
</ul>

Demo: http://plnkr.co/edit/eGohFqiGKmkonmLwT3g1?p=preview

CSS solution

However, when possible try to do such things with CSS only, this would be the optimal solution and no JS required:

ul li span {display: none;}
ul li:hover span {display: inline;}

Questions:
Answers:

I would simply make the assignment happen in the ng-mouseover and ng-mouseleave; no need to bother js file 🙂

<ul ng-repeat="task in tasks">
    <li ng-mouseover="hoverEdit = true" ng-mouseleave="hoverEdit = false">{{task.name}}</li>
    <span ng-show="hoverEdit"><a>Edit</a></span>
</ul>

Questions:
Answers:

I’d probably change your example to look like this:

<ul ng-repeat="task in tasks">
  <li ng-mouseover="enableEdit(task)" ng-mouseleave="disableEdit(task)">{{task.name}}</li>
  <span ng-show="task.editable"><a>Edit</a></span>
</ul>

//js
$scope.enableEdit = function(item){
  item.editable = true;
};

$scope.disableEdit = function(item){
  item.editable = false;
};

I know it’s a subtle difference, but makes the domain a little less bound to UI actions. Mentally it makes it easier to think about an item being editable rather than having been moused over.

Example jsFiddle: http://jsfiddle.net/jwcarroll/u8fHc/

Questions:
Answers:

A little late here, but I’ve found this to be a common problem worth a custom directive to handle. Here’s how that might look:

  .directive('toggleOnHover', function(){
    return {
      restrict: 'A',
      link: link
    };

    function link(scope, elem, attrs){
      elem.on('mouseenter', applyToggleExp);
      elem.on('mouseleave', applyToggleExp);

      function applyToggleExp(){
        scope.$apply(attrs.toggleOnHover);
      }
    }

  });

You can use it like this:

<li toggle-on-hover="editableProp = !editableProp">edit</li> 

Questions:
Answers:

Here is example with only CSS for that.
In example I’m using SASS and SLIM.

https://codepen.io/Darex1991/pen/zBxPxe

Slim:

a.btn.btn--joined-state
  span joined
  span leave

SASS:

=animate($property...)
  @each $vendor in ('-webkit-', '')
    #{$vendor}transition-property: $property
    #{$vendor}transition-duration: .3s
    #{$vendor}transition-timing-function: ease-in

=visible
  +animate(opacity, max-height, visibility)
  max-height: 150px
  opacity: 1
  visibility: visible

=invisible
  +animate(opacity, max-height, visibility)
  max-height: 0
  opacity: 0
  visibility: hidden

=transform($var)
  @each $vendor in ('-webkit-', '-ms-', '')
    #{$vendor}transform: $var

.btn
  border: 1px solid blue

  &--joined-state
    position: relative
    span
      +animate(opacity)

    span:last-of-type
      +invisible
      +transform(translateX(-50%))
      position: absolute
      left: 50%

    &:hover
      span:first-of-type
        +invisible
      span:last-of-type
        +visible
        border-color: blue

Questions:
Answers:

Even you can do this without any methods

    {{task.name}}

    Edit