Identifying Shifts in Objects Using Angular 5

Question

Identifying Shifts in Objects Using Angular 5

Is there a way to detect changes in an object connected to a large form? My goal is to display save/cancel buttons at the bottom of the page whenever a user makes changes to the input.

One approach I considered was creating a copy of the object and using *ngIf="object !== object_copy". If the user hits cancel, I would simply revert back to the copied object. However, I'm not sure if this method is efficient since it involves doubling the variables for a simple task. I'm relatively new to Angular and struggling to implement this method as making a copy seems to cause the object to lose its type.

I'm seeking guidance or suggestions on alternative methods to achieve this. Can anyone assist me with this issue?

javascript angular typescript

Answer 1

Answer №1

If you happen to be utilizing a Form, Angular's form control feature can be quite useful. It provides notifications whenever a form or any of its values are modified in any way. Here is a simple example of how you could utilize this:

form.dirty

You can also target specific fields for more focused functionality. The possibilities with reactive and template forms in Angular are endless.

https://angular.io/guide/forms

Answer 2

If you happen to be utilizing a Form, Angular's form control feature can be quite useful. It provides notifications whenever a form or any of its values are modified in any way. Here is a simple example of how you could utilize this:

form.dirty

You can also target specific fields for more focused functionality. The possibilities with reactive and template forms in Angular are endless.

https://angular.io/guide/forms

Answer 3

Answer №2

To properly handle the change event, you must subscribe to an event as shown below:

constructor(private formBuilder: FormBuilder) {
    this.myForm = formBuilder.group({
      name: 'Alice Smith',
      age: 30
    })

    this.myForm.valueChanges.subscribe(data => {
      console.log('Form data has changed', data);
    })
  }

This implementation should function correctly.

Answer 4

To properly handle the change event, you must subscribe to an event as shown below:

constructor(private formBuilder: FormBuilder) {
    this.myForm = formBuilder.group({
      name: 'Alice Smith',
      age: 30
    })

    this.myForm.valueChanges.subscribe(data => {
      console.log('Form data has changed', data);
    })
  }

This implementation should function correctly.

Answer 5

Answer №3

A feature in ReactiveForm is the dirty property which allows you to easily check the form's dirty status with 'myForm.dirty'.

If you want to set the initial value of the form to an object property, you can achieve this by using the getRawValue() method.

this.initialFormValue = this.myForm.getRawValue();

To monitor form changes, simply subscribe to the form using:

myForm.valueChanges.subscribe((value) => {

  this.updatedFormValue = this.myForm.getRawValue();

},
(err) => {
//
}
);

With both the initial and current form values, you can now compare them and proceed accordingly.

Answer 6

A feature in ReactiveForm is the dirty property which allows you to easily check the form's dirty status with 'myForm.dirty'.

If you want to set the initial value of the form to an object property, you can achieve this by using the getRawValue() method.

this.initialFormValue = this.myForm.getRawValue();

To monitor form changes, simply subscribe to the form using:

myForm.valueChanges.subscribe((value) => {

  this.updatedFormValue = this.myForm.getRawValue();

},
(err) => {
//
}
);

With both the initial and current form values, you can now compare them and proceed accordingly.

Identifying Shifts in Objects Using Angular 5

Answer №1

Answer №2

Answer №3

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