Update the ng-click event handler in Angular.js

Question

Update the ng-click event handler in Angular.js

I have a function defined in a directive called old(), currently the button executes this function when clicked. I want the old() function to be replaced with a new() function when the directive is loaded. The new function should receive (this.form) as a parameter, where "form" represents the name of my form. I attempted the following, but it did not work:

attrs.$set('ngClick', 'new(this.form)');

The new() function did not execute as expected. How can I achieve this? I specifically need to make these changes within a directive; while it might be possible in a controller, I am looking for a solution within a directive so that I could apply it to my actual project. Thank you.

http://jsfiddle.net/mg8g138x/

    app.directive('validation', function ($timeout) {

        return {
            restrict: 'AE',
            require: 'ngModel', 

            link: function (scope, element, attrs, ngModel) {
              if (!ngModel){
                return;          
              }

              scope.old= function(){
                alert("old")
              } 
             //attrs.$set('ngClick', 'new(this.form)');
              scope.new= function(form){
                alert("new");
                console.log(form)
              }                  

           }

        };
    });

javascript angularjs

Answer 1

Answer №1

There is a solution that involves creating a function to handle the use cases of two other functions you need to implement. For example, if you want function x to be triggered at the start and then function y to be triggered after a certain action, these can be called within the old() function.

I would advise against changing attributes, but if you still want to proceed, here is one way you could approach it:

app.directive('validation', function ($timeout) {

            return {
                restrict: 'AE',
                require: 'ngModel', 

                link: function (scope, element, attrs, ngModel) {
                  if (!ngModel){
                    return;          
                  }

                  scope.previous= function(){
                    alert("old")
                  }

                 scope.old= scope.previous 

                  scope.new= function(form){
                    alert("new");
                    console.log(form)
                  }
                 // This action should ideally be done within a separate function after an event or using $emit/$broadcast instead of directly in the code.
                 attrs.$set('ngClick', scope.old = scope.new); 
               }

            };
        });

You may also find this Stack Overflow discussion helpful: attrs.$set('ngClick', functionName + '()'); no longer working in angular 1.2rc3

Answer 2

There is a solution that involves creating a function to handle the use cases of two other functions you need to implement. For example, if you want function x to be triggered at the start and then function y to be triggered after a certain action, these can be called within the old() function.

I would advise against changing attributes, but if you still want to proceed, here is one way you could approach it:

app.directive('validation', function ($timeout) {

            return {
                restrict: 'AE',
                require: 'ngModel', 

                link: function (scope, element, attrs, ngModel) {
                  if (!ngModel){
                    return;          
                  }

                  scope.previous= function(){
                    alert("old")
                  }

                 scope.old= scope.previous 

                  scope.new= function(form){
                    alert("new");
                    console.log(form)
                  }
                 // This action should ideally be done within a separate function after an event or using $emit/$broadcast instead of directly in the code.
                 attrs.$set('ngClick', scope.old = scope.new); 
               }

            };
        });

You may also find this Stack Overflow discussion helpful: attrs.$set('ngClick', functionName + '()'); no longer working in angular 1.2rc3

Answer 3

Answer №2

It seems that the issue with your new function not working is due to AngularJS already compiling the template and linking all directives before your link function runs.

If you want to make changes to the ng-click value for a new function, you will need to re-compile the directive to see the effect of that change.

You can explore the AngularJS $compile service to understand how it can be utilized: https://docs.angularjs.org/api/ng/service/$compile.

Instead of directly changing the ng-click to a new function, consider utilizing JavaScript's functional programming feature. You can combine the old and new functions into one single function and choose which function to call using parameters. Here is an example:

 // Sample code snippet
link: function (scope, element, attrs, ngModel) {
    if (!ngModel){
        return;          
    }

    scope.old = function(){
        alert("old");
    }

    scope.new = function(form){
        alert("new");
        console.log(form)
    }

    scope.current = scope.old; // Control which function is called
    scope.form = ''; // Parameter for function called via ng-click

    scope.binding_to_button = function(function_to_call, parameter) {
        function_to_call(parameter);
    }

    scope.current = scope.new;
    scope.form = form;
}

Instead of binding scope.new or scope.old directly to ng-click, bind scope.binding_to_button.

ng-click="binding_to_button(current, form)"

This way, you can dynamically control which function is called and what parameters are passed to them through the click event using $scope.current and $scope.form.

Answer 4

It seems that the issue with your new function not working is due to AngularJS already compiling the template and linking all directives before your link function runs.

If you want to make changes to the ng-click value for a new function, you will need to re-compile the directive to see the effect of that change.

You can explore the AngularJS $compile service to understand how it can be utilized: https://docs.angularjs.org/api/ng/service/$compile.

Instead of directly changing the ng-click to a new function, consider utilizing JavaScript's functional programming feature. You can combine the old and new functions into one single function and choose which function to call using parameters. Here is an example:

 // Sample code snippet
link: function (scope, element, attrs, ngModel) {
    if (!ngModel){
        return;          
    }

    scope.old = function(){
        alert("old");
    }

    scope.new = function(form){
        alert("new");
        console.log(form)
    }

    scope.current = scope.old; // Control which function is called
    scope.form = ''; // Parameter for function called via ng-click

    scope.binding_to_button = function(function_to_call, parameter) {
        function_to_call(parameter);
    }

    scope.current = scope.new;
    scope.form = form;
}

Instead of binding scope.new or scope.old directly to ng-click, bind scope.binding_to_button.

ng-click="binding_to_button(current, form)"

This way, you can dynamically control which function is called and what parameters are passed to them through the click event using $scope.current and $scope.form.

Update the ng-click event handler in Angular.js

Answer №1

Answer №2

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