Angular Forms and Validations

12 Mar 2024

Intermediate

8.83K Views

6 min read

Angular Forms and Validations

Forms are the mandatory building blocks of a web application. You use forms for various activities like user login or signup, booking a flight, placing an order, etc. In this Angular tutorial, you will learn about different ways of creating forms in Angular. Angular provides two ways to create forms: Template-Driven and Model-Driven.

Angular Forms and Validations

Exploring an Angular course can delve deeper into these form-creation methods, providing comprehensive insights into the Template-driven and Model-Driven approaches, enabling individuals to choose the most suitable method for their application development needs.

Read More: What is Angular?

Angular Form Building Blocks

The basic building blocks of an Angular form are:

FormsGroup
FormControl
FormArray
Validations

Angular Form Building Blocks

Angular Form and Form Controls States

Angular Forms and their controls do change in their states as the user starts interaction with the form input controls. This state transition is helpful to get information about the form and its input control state. Based on the get information you can show or hide error messages and even you can check the validity of the form.

Angular Form and Form Controls States

States Transition

untouched => touched
invalid => valid
pristine => dirty

Angular Form Validations

Angular Form Validations are based on HTML5 validations. Angular Form Validations validate the user input for accuracy and completeness. All validations are performed on the client side.

Angular Forms Built-In Validation

required
minlength
maxlength
pattern
email – supports in Ng4
min
max

Template Driven Form

In template-driven forms, we don't create Angular form control objects but Angular directives create them for us using the information from our data binding configuration.

We don't have to push and pull data values because Angular handles that for you using the ngModel directive and Angular updates the mutable data model according to user changes as they happen while using the form.

Template-driven Form is set up and configured in HTML Code. Template-driven Form is easy to use and suits simple forms. Template-driven Form uses directives (ngForm, ngModel) and reference names (#refName) for creating forms.

Model-Driven Form

The model-driven form is set up and configured in the component class. It is based on a reactive style of programming where you use the underlying APIs FormControl and FormGroup that track the value and validation status. Reactive forms offer ease of testing and validation.

Template-Driven vs. Model-Driven Form

Template Driven

Model-Driven Form

The form is set up and configured in HTML Code

The form is set up and configured in the component class using FormBuilder

Easy and suited for simple form

Flexible and suited for complex form

Two-way data binding

No data binding(immutable data model)

Automatically track form and input element state

Reactive Transformation that can react to changes in data across the app

The form is passed to the component class via ngSubmit()

The form can be accessed in the component class without passing it via ngSubmit()

Unit Testing is complex

Unit Testing is easy

Neither of them is better than the other. Template-driven and Model-driven are two different architectural paradigms with their pros and cons so we can choose the approach that works best for you or according to our business requirements. This way, we are free to decide to use both in the same application accordingly.

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What do you think?

Forms are almost always present in any website or application because user input is one of the commonly used required features. Forms can be used to perform countless data-entry tasks such as account creation, login, placing orders, finding records, online bidding, and so on. Delving into Angular Training can offer in-depth insights into leveraging Angular for building robust and interactive forms.

Building easy-to-use forms requires design and user experience skills, as well as a framework with support for two-way data binding, change tracking, validation, and error handling such as Angular.