Validating Date of Birth in Angular Reactive Form: Best Practices and Examples
In your HTML file: You have an input field of type "date" with the formControlName "dateOfBirth" . Below that, you have an <div> element with a *ngIf directive to display an error message if the "dateOfBirth" form control has the "invalidDateOfBirth" error. In your TypeScript file: You import the necessary dependencies: FormControl, FormGroup, and FormBuilder from '@angular/forms' . Then, you define a FormGroup named "form" in your component. In the constructor, you inject the FormBuilder and use it to create the form group. The "dateOfBirth" form control is initialized with an empty string as its initial value and a custom validator function named "validateDateOfBirth" . The "validateDateOfBirth" function takes a FormControl as a parameter. It retrieves the value of the control, which is the date of birth entered by the user. It then calls the "calculateAge" function to...