Creating an Angular directive that deals with transient local variables

Question

Creating an Angular directive that deals with transient local variables

I am working on developing a directive that will allow me to create temporary variables within the scope of an HTML tag. This directive will only apply within the specific tag I am rendering. Here is an example use case:

<div class="input-group" ng-local="opened = false" ng-blur="opened = false;">
    <input type="text" class="form-control" uib-datepicker-popup="longDate" ng-model="start" is-open="opened" ng-focus="opened = true;" />
    <span class="input-group-btn">
        <button type="button" ng-click="opened = true;" class="fa fa-calendar" ></button>
    </span>
</div>

In this scenario, the ng-local directive creates a variable called opened and initializes it with a value of false. The content inside the directive is a transcluded template. The benefit of this approach is that multiple datepickers on a page can all share the same variable opened, eliminating the need for separate variables in the scope or controller just for temporary use within a div. However, I want this directive to be versatile enough to handle different use cases without creating multiple variations.

While my initial implementation was successful, I encountered a problem where the parent scope variable start was not being accessed correctly by the datepicker component. Since I am not very experienced with the $transclude functionality, I am seeking guidance from someone who can help me troubleshoot this issue. Below is the current version of the directive I have implemented:

(function () {
    angular.module('myApp').directive('ngLocal', [function () {
        return {
            restrict: 'A',
            transclude: 'element',
            replace: false,
            scope: {
                ngLocal: '@'
            },
            link: function ngLocalLink(directiveScope, element, attrs, ctrl, $transclude) {
                $transclude(directiveScope, function ngLocalTransclude(clone, scope) {
                    element.empty();
                    element.replaceWith(clone);
                    scope.$eval(directiveScope.ngLocal);
                });
            }
        };
    }]);
})();

Any insights or suggestions would be greatly appreciated!

EDIT

For reference, here's a plunkr link:

https://plnkr.co/edit/pog2bcxEf8mDEb2vIVjP?p=preview

javascript angularjs angularjs-directive angularjs-ng-transclude

Answer 1

Answer №1

Instead of using transclude in your directive, you can simply create a child or isolate scope.

Here is an example:

angular.module('myApp', ['ngAnimate', 'ui.bootstrap']);

// CONTROLLER
angular.module('myApp').controller('myController', function($scope) {
  $scope.dates = {
      workingDate : new Date(),
      brokenDate1 : new Date(),
      brokenDate2 : new Date(),
      localDate : new Date(),
  }
});

// DIRECTIVE
angular.module('myApp').directive('ngLocal', [
  function() {
    return {
      restrict: 'A',
      replace: false,
      scope: true //directive have own scope
    };
  }
]);

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.js"></script>
<script src="//ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular-animate.js"></script>
<script src="//angular-ui.github.io/bootstrap/ui-bootstrap-tpls-1.1.0.js"></script>
<link href="//netdna.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet">

<div ng-app="myApp">
  <div ng-controller="myController">
    <h4>This one works</h4>
    <div class="input-group">
      <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="workingOpen" ng-model="dates.workingDate" />
      <span class="input-group-btn">
        <button class="btn btn-secondary" type="button" ng-click="workingOpen = true" >OPEN</button>
      </span>
    </div>

    <br/>
    <br/>
    <br/>

    <h4>This is the problem I'm trying to solve</h4>
    <h4>Both datepickers use "brokenOpen" so they both open whenever either is clicked</h4>
    <div style="width: 40%; display: inline-block;" ng-local>
      <div class="input-group">
        <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="brokenOpen" ng-model="dates.brokenDate1" />
        <span class="input-group-btn">
          <button class="btn btn-secondary" type="button" ng-click="brokenOpen = true" >OPEN</button>
        </span>
      </div>
    </div>
    <div style="width: 40%;  display: inline-block;" ng-local>
      <div class="input-group">
        <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="brokenOpen" ng-model="dates.brokenDate2" />
        <span class="input-group-btn">
          <button class="btn btn-secondary" type="button" ng-click="brokenOpen = true" >OPEN</button>
        </span>
      </div>
    </div>

    <br/>
    <br/>
    <br/>

    <h4>This is using my directive</h4>
    <h4>The date does not update correctly to the parent scope</h4>

    <div class="input-group" ng-local="localOpen = false">
      <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="localOpen" ng-model="dates.localDate" />
      <span class="input-group-btn">
              <button class="btn btn-secondary" type="button" ng-click="localOpen = true;" >OPEN</button>
          </span>
    </div>

    <label>See how the date is not updating: {{dates.localDate}}</label>
  </div>
</div>

Answer 2

Instead of using transclude in your directive, you can simply create a child or isolate scope.

Here is an example:

angular.module('myApp', ['ngAnimate', 'ui.bootstrap']);

// CONTROLLER
angular.module('myApp').controller('myController', function($scope) {
  $scope.dates = {
      workingDate : new Date(),
      brokenDate1 : new Date(),
      brokenDate2 : new Date(),
      localDate : new Date(),
  }
});

// DIRECTIVE
angular.module('myApp').directive('ngLocal', [
  function() {
    return {
      restrict: 'A',
      replace: false,
      scope: true //directive have own scope
    };
  }
]);

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.js"></script>
<script src="//ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular-animate.js"></script>
<script src="//angular-ui.github.io/bootstrap/ui-bootstrap-tpls-1.1.0.js"></script>
<link href="//netdna.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet">

<div ng-app="myApp">
  <div ng-controller="myController">
    <h4>This one works</h4>
    <div class="input-group">
      <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="workingOpen" ng-model="dates.workingDate" />
      <span class="input-group-btn">
        <button class="btn btn-secondary" type="button" ng-click="workingOpen = true" >OPEN</button>
      </span>
    </div>

    <br/>
    <br/>
    <br/>

    <h4>This is the problem I'm trying to solve</h4>
    <h4>Both datepickers use "brokenOpen" so they both open whenever either is clicked</h4>
    <div style="width: 40%; display: inline-block;" ng-local>
      <div class="input-group">
        <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="brokenOpen" ng-model="dates.brokenDate1" />
        <span class="input-group-btn">
          <button class="btn btn-secondary" type="button" ng-click="brokenOpen = true" >OPEN</button>
        </span>
      </div>
    </div>
    <div style="width: 40%;  display: inline-block;" ng-local>
      <div class="input-group">
        <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="brokenOpen" ng-model="dates.brokenDate2" />
        <span class="input-group-btn">
          <button class="btn btn-secondary" type="button" ng-click="brokenOpen = true" >OPEN</button>
        </span>
      </div>
    </div>

    <br/>
    <br/>
    <br/>

    <h4>This is using my directive</h4>
    <h4>The date does not update correctly to the parent scope</h4>

    <div class="input-group" ng-local="localOpen = false">
      <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="localOpen" ng-model="dates.localDate" />
      <span class="input-group-btn">
              <button class="btn btn-secondary" type="button" ng-click="localOpen = true;" >OPEN</button>
          </span>
    </div>

    <label>See how the date is not updating: {{dates.localDate}}</label>
  </div>
</div>

Answer 3

Answer №2

Experience the power of nested directives by utilizing an outer directive to encapsulate data and an inner directive to retrieve data from a function provided by the outer directive.

To see a demonstration, click on this link: https://plnkr.co/edit/4n6kf40ZMf7lRCad5ofe?p=preview

Here is the code snippet:

angular.module('myapp', [])
  .directive('outer', function () {
    return {
      restrict: 'E',
      transclude: true,
      scope: {
        value: '='
      },
      template: function(element, attrs) {
        return '<div>outer! value = {{value}}<div ng-transclude></div></div>';
      },
      controller: function($scope) {
        this.getValue = function() {
          return $scope.value;
        }
      }
    }
  })
  .directive('inner', function () {
    return {
      restrict: 'E',
      template: function(element, attrs) {
        return '<div>inner! value = {{value}}</div>';
      },
      require: '^outer',
      link: function (scope, element, attrs, parentCtrl) {
        scope.$watch(
          function() {
            return parentCtrl.getValue();
          }, function(oldValue, newValue) {
            scope.value = parentCtrl.getValue();
          }
        );
      }
    }
  });

Answer 4

Experience the power of nested directives by utilizing an outer directive to encapsulate data and an inner directive to retrieve data from a function provided by the outer directive.

To see a demonstration, click on this link: https://plnkr.co/edit/4n6kf40ZMf7lRCad5ofe?p=preview

Here is the code snippet:

angular.module('myapp', [])
  .directive('outer', function () {
    return {
      restrict: 'E',
      transclude: true,
      scope: {
        value: '='
      },
      template: function(element, attrs) {
        return '<div>outer! value = {{value}}<div ng-transclude></div></div>';
      },
      controller: function($scope) {
        this.getValue = function() {
          return $scope.value;
        }
      }
    }
  })
  .directive('inner', function () {
    return {
      restrict: 'E',
      template: function(element, attrs) {
        return '<div>inner! value = {{value}}</div>';
      },
      require: '^outer',
      link: function (scope, element, attrs, parentCtrl) {
        scope.$watch(
          function() {
            return parentCtrl.getValue();
          }, function(oldValue, newValue) {
            scope.value = parentCtrl.getValue();
          }
        );
      }
    }
  });

Answer 5

Answer №3

Consider utilizing $parent.localDate instead of the current method.

<div class="input-group" ng-local="localOpen = false">
      <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="localOpen" ng-model="$parent.localDate" />
      <span class="input-group-btn">
          <button class="btn btn-secondary" type="button" ng-click="localOpen = true;" >OPEN</button>
      </span>
</div>

If avoiding $parent, you can utilize the isolated scope and define the desired variable:

<div class="input-group" ng-local="localOpen = false" date="localDate">
      <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="localOpen"  ng-model="date" />
      <span class="input-group-btn">
          <button class="btn btn-secondary" type="button" ng-click="localOpen = true;" >OPEN</button>
      </span>
</div>

angular.module('myApp').directive('ngLocal', [function () {
return {
    restrict: 'A',
    transclude: 'element',
    replace: false,
    scope: {
        ngLocal: '@',
        date: '='
    },
    link: function ngLocalLink(directiveScope, element, attrs, ctrl, $transclude) {
        $transclude(directiveScope, function ngLocalTransclude(clone, scope) {
            element.empty();
            element.replaceWith(clone);
            scope.$eval(directiveScope.ngLocal);
        });
    }
};
}]);

For more details, check out the updated plunker here: https://plnkr.co/edit/4zrNzbSc5IwqqbE2ISE1?p=preview

Answer 6

Consider utilizing $parent.localDate instead of the current method.

<div class="input-group" ng-local="localOpen = false">
      <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="localOpen" ng-model="$parent.localDate" />
      <span class="input-group-btn">
          <button class="btn btn-secondary" type="button" ng-click="localOpen = true;" >OPEN</button>
      </span>
</div>

If avoiding $parent, you can utilize the isolated scope and define the desired variable:

<div class="input-group" ng-local="localOpen = false" date="localDate">
      <input type="text" class="form-control" uib-datepicker-popup="longDate" is-open="localOpen"  ng-model="date" />
      <span class="input-group-btn">
          <button class="btn btn-secondary" type="button" ng-click="localOpen = true;" >OPEN</button>
      </span>
</div>

angular.module('myApp').directive('ngLocal', [function () {
return {
    restrict: 'A',
    transclude: 'element',
    replace: false,
    scope: {
        ngLocal: '@',
        date: '='
    },
    link: function ngLocalLink(directiveScope, element, attrs, ctrl, $transclude) {
        $transclude(directiveScope, function ngLocalTransclude(clone, scope) {
            element.empty();
            element.replaceWith(clone);
            scope.$eval(directiveScope.ngLocal);
        });
    }
};
}]);

For more details, check out the updated plunker here: https://plnkr.co/edit/4zrNzbSc5IwqqbE2ISE1?p=preview

Answer 7

Answer №4

I was hoping to achieve similar functionality to that of ng-repeat, where I wouldn't have to refer to everything through the parent scope in the transcluded element.

ng-repeat does not utilize an isolate scope but instead, it uses an inherited scope.

To learn more about directive scopes, you can visit the AngularJS $compile Service API Reference -- scope.

Example

This custom directive transcludes its contents multiple times, creating a new inherited scope each time. The number of repetitions is specified by the repeat attribute.

angular.module('myApp').directive('repeat', function () {
    return{
        scope: false,
        transclude: 'element',
        link : function(scope, element, attrs, ctrl, transcludeFn){
            var parent = element.parent();
            var repeatNum = attrs.repeat;
            for(var i = 1;i<= repeatNum;++i){
                var childScope = scope.$new();
                childScope.$index = i;
                transcludeFn(childScope, function (clone) {
                    parent.append(clone);
                })
            }
        }
    }
})

Check out the DEMO on JSFiddle

Answer 8

I was hoping to achieve similar functionality to that of ng-repeat, where I wouldn't have to refer to everything through the parent scope in the transcluded element.

ng-repeat does not utilize an isolate scope but instead, it uses an inherited scope.

To learn more about directive scopes, you can visit the AngularJS $compile Service API Reference -- scope.

Example

This custom directive transcludes its contents multiple times, creating a new inherited scope each time. The number of repetitions is specified by the repeat attribute.

angular.module('myApp').directive('repeat', function () {
    return{
        scope: false,
        transclude: 'element',
        link : function(scope, element, attrs, ctrl, transcludeFn){
            var parent = element.parent();
            var repeatNum = attrs.repeat;
            for(var i = 1;i<= repeatNum;++i){
                var childScope = scope.$new();
                childScope.$index = i;
                transcludeFn(childScope, function (clone) {
                    parent.append(clone);
                })
            }
        }
    }
})

Check out the DEMO on JSFiddle

Creating an Angular directive that deals with transient local variables

Answer №1

Answer №2

Answer №3

Answer №4

Example

Similar questions

What is the process for retrieving AngularJS parameters in a Java backend system?

Learn how to utilize ng-class to assign an ID selector to HTML elements

Combining nested objects into a single object

Utilizing titanium to develop a functionality that listens for button presses on any area of the screen

Using default JavaScriptSerializer to bind DateTime to knockout view model

JavaScript is unable to activate the button once it has been disabled

Redux: streamlining containers, components, actions, and reducers for seamless organization

Issue with NodeJS: Unable to locate module 'io' (socket.io in combination with express version 4.15.3)

Managing various encoding methods when retrieving the XML data feed

Is it possible for the Jquery Accordion to retract on click?

Nuxt Vuex global state update does not cause v-for loop components to re-render

Is it possible to determine the number of JSON properties without the need for a loop?

What is the best way to target the iframe within the wysihtml5 editor?

What is the best way to showcase search results using Bootstrap?

Verify the validity of the user's input

Creating a jsp page content with jquery and retrieving request parameters

I'm currently working with ReactJS and attempting to retrieve JSON data from a REST API in JIRA, but I'm facing challenges in achieving this

Clicking on the image "Nav" will load the div into the designated target and set its display to none. The div will

Elements overlapped with varying opacities and responsive to mouse hovering

Mastering the art of invoking a JavaScript function from a GridView Selected Index Changed event