Angular: Monitoring changes in forms

Question

Angular: Monitoring changes in forms

Currently, I am working on developing an Angular application where I need to monitor any changes in the form and execute specific operations based on those changes. While I am aware that this can be done using $scope.watch, I am concerned about the impact it may have on performance.

My Objective

The scenario involves a pre-filled form, where I plan to use angular.copy() to create a reference for the form data and compare it to the original data.

I attempted to utilize $parsers for this task but faced difficulties. Is there an alternative method to accomplish this effectively?

javascript angularjs

Answer 1

Answer №1

To handle changing user input, you can utilize the ng-change directive.
According to the information provided in the official documentation, "The given expression is executed when a user modifies the input field. Unlike the JavaScript onchange event, which typically triggers after the change is complete (such as when the user leaves the form element or presses the return key)."
For more insights on this topic, check out this article: Distinguishing ng-change from $watch

Answer 2

To handle changing user input, you can utilize the ng-change directive.
According to the information provided in the official documentation, "The given expression is executed when a user modifies the input field. Unlike the JavaScript onchange event, which typically triggers after the change is complete (such as when the user leaves the form element or presses the return key)."
For more insights on this topic, check out this article: Distinguishing ng-change from $watch

Answer 3

Answer №2

Have you attempted using ng-change? This enables a function to be called when the value of ng-model changes.

<input type="search"  ng-change="changeValue()"  ng-model="test" name="test"/>

If you want to identify which field triggers the function, you can include the field name as a string parameter.

<input type="search"  ng-change="changeValue('field1')"  ng-model="field1" name="field1"/>

Remember in the controller to declare the function changeValue within the scope.

 $scope.changeValue = function(fieldname){
    switch (fieldname){
        case 'field1' : .... break;
        case 'field2' : .... break;     
        case 'field3' : .... break;
        ...
    }
 }

Answer 4

Have you attempted using ng-change? This enables a function to be called when the value of ng-model changes.

<input type="search"  ng-change="changeValue()"  ng-model="test" name="test"/>

If you want to identify which field triggers the function, you can include the field name as a string parameter.

<input type="search"  ng-change="changeValue('field1')"  ng-model="field1" name="field1"/>

Remember in the controller to declare the function changeValue within the scope.

 $scope.changeValue = function(fieldname){
    switch (fieldname){
        case 'field1' : .... break;
        case 'field2' : .... break;     
        case 'field3' : .... break;
        ...
    }
 }

Answer 5

Answer №3

If you need to determine whether any changes have been made to a duplicated object compared to the original data, angular.equals comes in handy.

angular.equals(copyObj, originalData)

This function performs a thorough comparison of the object and its embedded sub-properties, indicating true if no modifications have occurred.

Answer 6

If you need to determine whether any changes have been made to a duplicated object compared to the original data, angular.equals comes in handy.

angular.equals(copyObj, originalData)

This function performs a thorough comparison of the object and its embedded sub-properties, indicating true if no modifications have occurred.

Angular: Monitoring changes in forms

Answer №1

Answer №2

Answer №3

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