Angular sets the required property only when the button is clicked

Question

Angular sets the required property only when the button is clicked

Is there a way to make a field required in Angular only when a button is clicked? Currently, the error message appears even before the user interacts with the field.

I would like the error message "folder name is required" to only appear when the user clicks the submit button and the field is empty. Any suggestions? Thank you.

private _createModelForm(): FormGroup {
    return this.formBuilder.group({
      propertyId: this.data.propertyId,
      folderName: new FormControl('', [
        Validators.required,
        Validators.pattern(/[a-zA-Z0-9\.\-]+.?/)
      ]),
      documentManagementFolderId:this.data.documentManagementFolderId
    });
  }




<mat-error *ngIf="modelForm.get('folderName').hasError('pattern')">
                    Folder name must not include special characters.
                </mat-error>

https://i.sstatic.net/QKNN7.png

angular typescript

Answer 1

Answer №1

Don't forget to validate the dirty and touched states as well

Here's an example of how to do it:

<mat-error *ngIf="(modelForm.get('folderName').dirty || modelForm.get('folderName').touched) && modelForm.get('folderName').hasError('pattern')">
                    Folder name should not contain special characters.
                </mat-error>

Answer 2

Don't forget to validate the dirty and touched states as well

Here's an example of how to do it:

<mat-error *ngIf="(modelForm.get('folderName').dirty || modelForm.get('folderName').touched) && modelForm.get('folderName').hasError('pattern')">
                    Folder name should not contain special characters.
                </mat-error>

Answer 3

Answer №2

Utilizing {updateOn:'submit'} can be beneficial, however, it requires careful attention to how the formGroup is constructed.

There are two distinct methods for creating a FormGroup:

1.- Using the constructor - involves using new FormGroup and new FormControl (note that formBuilder is not utilized but each control must have a new FormControl, refer to the documentation)

return new FormGroup({
      propertyId: new FormControl(this.data.propertyId), //<--each property
                                                         // is a new FormControl
      folderName: new FormControl('', [
        Validators.required,
        Validators.pattern(/[a-zA-Z0-9\.\-]+.?/)
      ]),
      documentManagementFolderId:new FormControl(this.data.documentManagementFolderId)
    },{updateOn:'submit'});

2.- Utilizing formBuilder - note that in this scenario, new FormControl or new FormArray are never used. If a nested formGroup or formArray is required, employ this.formBuilder.group and this.formBuilder.array as demonstrated in the documentation

return this.formBuilder.group({
      propertyId: this.data.propertyId,
      folderName: ['', [              //<--see that is not new FormControl
        Validators.required,
        Validators.pattern(/[a-zA-Z0-9\.\-]+.?/)
      ]],
      documentManagementFolderId:this.data.documentManagementFolderId
    },{updateOn:'submit'});

(*)NOTE: The use of updateOn applies to the entire form but can also be implemented on individual FormControls.

Answer 4

Utilizing {updateOn:'submit'} can be beneficial, however, it requires careful attention to how the formGroup is constructed.

There are two distinct methods for creating a FormGroup:

1.- Using the constructor - involves using new FormGroup and new FormControl (note that formBuilder is not utilized but each control must have a new FormControl, refer to the documentation)

return new FormGroup({
      propertyId: new FormControl(this.data.propertyId), //<--each property
                                                         // is a new FormControl
      folderName: new FormControl('', [
        Validators.required,
        Validators.pattern(/[a-zA-Z0-9\.\-]+.?/)
      ]),
      documentManagementFolderId:new FormControl(this.data.documentManagementFolderId)
    },{updateOn:'submit'});

2.- Utilizing formBuilder - note that in this scenario, new FormControl or new FormArray are never used. If a nested formGroup or formArray is required, employ this.formBuilder.group and this.formBuilder.array as demonstrated in the documentation

return this.formBuilder.group({
      propertyId: this.data.propertyId,
      folderName: ['', [              //<--see that is not new FormControl
        Validators.required,
        Validators.pattern(/[a-zA-Z0-9\.\-]+.?/)
      ]],
      documentManagementFolderId:this.data.documentManagementFolderId
    },{updateOn:'submit'});

(*)NOTE: The use of updateOn applies to the entire form but can also be implemented on individual FormControls.

Answer 5

Answer №3

Essentially, the solution provided by @robert is accurate. However, I can suggest an alternative approach if you are inclined to only display the message after clicking a button.

Start by declaring a variable named submitted = false within your component
In your submit function, assign submitted = true

Next, in the HTML file:

<mat-error *ngIf="modelForm.get('folderName').hasError('pattern') && submitted">
   The folder name must not contain special characters.
</mat-error>

Answer 6

Essentially, the solution provided by @robert is accurate. However, I can suggest an alternative approach if you are inclined to only display the message after clicking a button.

Start by declaring a variable named submitted = false within your component
In your submit function, assign submitted = true

Next, in the HTML file:

<mat-error *ngIf="modelForm.get('folderName').hasError('pattern') && submitted">
   The folder name must not contain special characters.
</mat-error>

Answer 7

Answer №4

To automate the process, I would approach it as follows:

handleButtonClick() {
    const folderControl = this.formModel.get('folderName');
    folderControl.setValidators([Validator.required, <any previous validators>]);
    folderControl.updateValueAndValidity();
}

Additionally, the default empty value should be set to null instead of '', if my understanding is correct.

Answer 8

To automate the process, I would approach it as follows:

handleButtonClick() {
    const folderControl = this.formModel.get('folderName');
    folderControl.setValidators([Validator.required, <any previous validators>]);
    folderControl.updateValueAndValidity();
}

Additionally, the default empty value should be set to null instead of '', if my understanding is correct.

Angular sets the required property only when the button is clicked

Answer №1

Answer №2

Answer №3

Answer №4

Similar questions

Retrieve information from two distinct observables from within the resolver function

Dynamic content within an Angular Swiper

Compiling TypeScript to JavaScript with Intellij IDEA while preserving the folder hierarchy

Height transition animation in Angular 2 - maintaining state consistency

Real-time dynamic routing in Angular

Develop a variety of Jabber client echo bots

Implementing an Asynchronous Limited Queue in JavaScript/TypeScript with async/await

Use Ramda to convert an array of objects into nested objects

Uncertain entities in Typescript

I am facing an issue with Angular reactive forms where the default values I set in ngOnInIt are not being reflected

The type 'ElementTypes' cannot be assigned to type 'ElementTypes.word'

Is a shallow copy created by spreading?

Locate and refine the pipeline for converting all elements of an array into JSON format using Angular 2

Is it necessary to include @types/ before each dependency in react native?

Using the `disableSince` option in `mydatepicker` for validating date of birth

Turning XSD into TypeScript code

Using an async option value in Angular passing technique

Submit file in Cypress while hiding input[type="file"] from DOM

Angular 6 is throwing an error stating that the 'publish' property is not found on the type Observable<string>

Achieving a Subset Using Functional Programming