Validation is a must in Angular 2

Question

Validation is a must in Angular 2

I am facing an issue with the default required validator in angular forms. My form has one input field and a submit button.

There are two important files:

example.form.ts
example.form.template.html

Here is my code setup:

In the .ts file, I create a form using the form builder:

exampleForm: FormGroup
constructor(protected fb: FormBuilder){
  this.exampleForm = fb.group({
    name: ['', Validators.required]
  });
}

get isFormValid: boolean {
  return this.exampleForm.valid;
}

Template section:

<form [formGroup]="exampleForm">
  <input type="text" formControlName="name">
  <button type="submit" [disabled]="!isFormValid" id="save-button">Submit</button>
</form>

Currently, when the input field is empty, the button stays disabled (as per the validator). But even if I enter something into the field, I can't directly click on the button - I have to first click outside the input field. How can I modify this behavior?

forms angular typescript

Answer 1

Answer №1

When the input field is focused, the form validation will not pass because from the form's perspective, the fields appear empty.

If you want a simple solution to ensure that the input fields are not empty, you can try this approach:

<form [formGroup]="exampleForm">
  <input type="text" formControlName="name" [(ngModel)]="someName">
  <button type="submit" [disabled]="someName==''" id="save-button">Submit</button>
</form>

With this code, the button will only be disabled if the fields are empty. For more complex validation requirements, like using regex, you may need to create a custom validation method. Here's an example:

isValidEmail(): ValidatorFn {
    return (control: FormControl): string[] => {
      if (!control || !control.value || control.value == "")
        return null;
      if (this.regexService.email.test(control.value))
        return null;

      return ["Invalid email"]
    };
  }

Make sure to initialize the validate method in formBuilder as shown below:

initFormGroup() {
    this.authenticateForm = this.formBuilder.group(
      {
        email: ['',
          this.isValidEmail()
        ],        
      }
    );
  }

Answer 2

When the input field is focused, the form validation will not pass because from the form's perspective, the fields appear empty.

If you want a simple solution to ensure that the input fields are not empty, you can try this approach:

<form [formGroup]="exampleForm">
  <input type="text" formControlName="name" [(ngModel)]="someName">
  <button type="submit" [disabled]="someName==''" id="save-button">Submit</button>
</form>

With this code, the button will only be disabled if the fields are empty. For more complex validation requirements, like using regex, you may need to create a custom validation method. Here's an example:

isValidEmail(): ValidatorFn {
    return (control: FormControl): string[] => {
      if (!control || !control.value || control.value == "")
        return null;
      if (this.regexService.email.test(control.value))
        return null;

      return ["Invalid email"]
    };
  }

Make sure to initialize the validate method in formBuilder as shown below:

initFormGroup() {
    this.authenticateForm = this.formBuilder.group(
      {
        email: ['',
          this.isValidEmail()
        ],        
      }
    );
  }

Validation is a must in Angular 2

Answer №1

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