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Gain insights into designing scalable Angular applications. Learn about components, directives, routing, RXJS, forms, and Firebase authentication to develop rich, interactive web solutions.

Angular Designing and Architecting Web Applications.png

angular-starter-v5.tar.gz

Angular

Angular Install Dependencies

Angular with Relaunch

This course will teach you step-by-step how to design and architect large Angular applications. 

You’ll start with the basics: components, pipes, and directives. These are the building blocks of any Angular application, so you will get plenty of hands-on practice with this material. Next, you’ll ramp things up by stepping into modules, routing, and RXJS, where you’ll learn how to declaratively manage data and dive deep into observables.

In the latter half of the course, you’ll cover reactive and template forms (crucial for handling user data), as well as custom validators and setting up authentication with Firebase.

By the end of this course, you'll be able to design large, scalable applications, be able to develop rich interactive components, and you’ll really understand how Angular works under the hood.

Angular: Designing and Architecting Web Applications

The next thing we'll look at is adding validation to our form. Template forms use HTML5 attributes to determine if an input should be validated. This is called constraint validation. You can find more information about it [here](https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/HTML5/Constraint_validation).

# Adding constraint attributes

There's a section on the page called **Validation-related attributes**. This is a list of attributes we can apply to the `<input>` element to perform validation. Let's update the `<input>` element in the `app.component.html` template file.

<div class="container">
  <div class="card mt-3">
    <form class="card-body" #emailFormGroup="ngForm">
      <label>E-mail</label>
      <input type="email" pattern=".+@.+\..+" required class="form-control" name="emailInput" [(ngModel)]="email">
      <div>Values: {{ emailFormGroup.value | json }}</div>
      <div>Valid: {{ emailFormGroup.valid }}</div>
      <hr class="mb-4">
      <button class="btn btn-primary" type="submit">
        Submit
      </button>
    </form>
  </div>
</div>

There are two attributes we're applying to the input. First, we're adding the `required` attribute to make it a requirement to provide a value for the input before submission. Behind the scenes, Angular will override the default behavior by running the value through the `Validators.required()` validator function.

The second attribute we're applying is called `pattern`. This will check the value against a regular expression. Like before, Angular will override the behavior by running the value through the `Validators.pattern()` validator function.

By using template forms, we can continue to use the native HTML5 attributes. Angular will understand what we're trying to do. It will run the values through its validator functions whenever it can.

# Outputting error messages

The next thing we'll handle is outputting an error message if the validation failed. First, we'll modify the `<input>` element.

```html
<input type="email" pattern=".+@.+\..+" required #emailFormControl="ngModel" class="form-control"
        name="emailInput" [(ngModel)]="email"
        [ngClass]="{ 'is-invalid': emailFormControl.invalid && emailFormControl.touched }">
```
Two things are going on here. First, we're creating a variable called `emailFormControl`. It's being set to `ngModel`. This will return a form control because we're declaring the variable on the `<input>`.

The second thing we're doing is binding a class, called `is-invalid`, if the validation fails, and the input has been touched. We must check if it has been touched before we output an error because Angular will run validation immediately. We don't want to annoy the user with an error message when they haven't had the chance to input a value.

Next, we'll add the error messages below the `<input>` element. We'll be replacing the `<div>` elements that we're using to log the form group and its properties.

There are two attributes we're applying to the input. First, we're adding the `required` attribute to make it a requirement to provide a value for the input before submission. Behind the scenes, Angular will override the default behavior by running the value through the `Validators.required()` validator function.

The second attribute we're applying is called `pattern`. This will check the value against a regular expression. Like before, Angular will override the behavior by running the value through the `Validators.pattern()` validator function.

By using template forms, we can continue to use the native HTML5 attributes. Angular will understand what we're trying to do. It will run the values through its validator functions whenever it can.

# Outputting error messages

The next thing we'll handle is outputting an error message if the validation failed. First, we'll modify the `<input>` element.

```html
<input type="email" pattern=".+@.+\..+" required #emailFormControl="ngModel"
        name="emailInput" [(ngModel)]="email"
        [ngClass]="{ 'is-invalid': emailFormControl.invalid && emailFormControl.touched }">
```
Two things are going on here. First, we're creating a variable called `emailFormControl`. It's being set to `ngModel`. This will return a form control because we're declaring the variable on the `<input>`.

The second thing we're doing is binding a class, called `is-invalid`, if the validation fails, and the input has been touched. We must check if it has been touched before we output an error because Angular will run validation immediately. We don't want to annoy the user with an error message when they haven't had the chance to input a value.

Next, we'll add the error messages below the `<input>` element. We'll be replacing the `<div>` elements that we're using to log the form group and its properties.

First Steps

Our First Project

Component Basics

Pipes

Directives

Modules

Routing

Advanced Components

Services

RxJS

Reactive Forms

Template Forms

Custom Validators

Authentication

Conclusion

Validation