Introduction to Build a Modern Angular Application with Signals

Course Introduction

Project Architecture Build a Modern Angular Application with Signals

Project Architecture

This module initiates your journey by highlighting the significance of lightweight dependencies, improved reactivity, and optimized performance in application development using Angular 17. Understand the reasons driving the upgrade from previous Angular versions to Angular 17.

Introduction

Getting started with the concept of signals

The Concept of Signals

The importance of Signals over Change Detection and Zone.js

In this lesson, you will learn how to create our first Signals variable in Angular. You get to see how easy it is to declare variables compared to doing it with Observables which has a more robust boilerplate code.

How to Create a Signal

Here, you will get to learn about the different Reactive primitives available in Signals, which are writable signals, computed and effects.

Reactive Primitives in Signals

Discover the foundational concept of Signals within Angular and its relevance in the ecosystem. Understand the pivotal role Signals play, addressing performance concerns and simplifying Angular application development.

 Getting Started with Signals

This video provides an insight into what we are going to do in this module.

Module 3 Introduction

In this module, you’ll learn how to combine RxJS and Signals when working with HTTP requests from the REST API. We will learn how to work with the Interoperability API when dealing with asynchronous operations in Signals.

Fetching Data from the Server using RxJS

Here we get to modify the code we wrote previously to fetch data from the server. We go ahead to show the simplicity of Signals by converting the data gotten from the Observable into Signals making use of the Interoperability API.

Using the Interoperability API to convert Http requests to Signals

Combine RxJS and Signals to navigate HTTP requests from REST APIs. Learn to leverage the Interoperability API for managing asynchronous operations within Signals.

Signals and Http Requests

Module 4 Introduction

In this module, we get to display how to spread data across different components with the use of Signals.

Adding Items to the Shopping Cart

In this module, we will utilise Signals to increase and decrease the number of items to add to cart =, as well as integrate functionality to remove an item from cart.

Integrate Counter Functionality and Remove Items from Cart

In this lesson, we get a summary of all the items that have been added to the cart, which includes the number of items bought and the cart total.

Implement the Checkout Page

Exercise

In this lesson, we will take a look at how to handle errors in Signals.

Error Handling in Signals

Explore the techniques of disseminating data across various components using Signals, facilitating efficient communication and data exchange.

Sharing Data Between Different Components with Signals

We will do a review of all the concepts learned in the course and also look at the upcoming features to be integrated into Signals.

Wrapping up the Course

In the final module, we comprehensively review every concept that's been covered in this course. Additionally, this module provides insights into upcoming features to be integrated into Angular 17 Signals.

Course Wrap Up

### How The Course Works:

- The "Build a Modern Web Application using Angular Signals" course is a comprehensive online program spanning five modules. Discover how to effectively utilize Signals to manage the entire state of an Angular application, integrate the newly built-in control flows, employ deferrable views, navigate components using lazy loaded routes, and implement Standalone components.
- Remote Access: Take advantage of the course from any location, allowing you the flexibility to engage with the materials at your convenience.
- Self-Paced Learning: Tailor your learning experience to your schedule, enabling you to progress through the course content at your own pace.
- Community Engagement: Collaborate and learn alongside a diverse community of fellow students, fostering an environment of shared knowledge and support.
- Structured Learning: Experience a well-organized curriculum designed to provide a cohesive and comprehensive understanding of Angular Signals in a logical progression.

### Understanding the Challenges

Learning Angular 17 can present various hurdles and frustrations for those new to the technology. As individuals navigate their journey into this advanced framework, they commonly encounter several challenges:

- Complexity Barrier: The intricate architecture and extensive feature set of Angular 17 can overwhelm newcomers, posing a significant learning curve.
- State Management Complexity: Managing the state of an Angular application efficiently, especially with the nuances of Signals, can prove challenging for learners.
- Integration Puzzles: Integrating and harnessing newly built-in control flows, deferrable views, Standalone components, and lazy loaded routes can be intricate and perplexing.
- Navigational Complexity: Understanding the intricacies of lazy loaded routes and effective navigation between components can pose obstacles to a smooth learning experience.

Navigating through these complexities without guidance can hinder the progress of aspiring developers aiming to master Angular 17.


### Advantages of Learning Angular 17 in 2023

- Enhanced Performance: In 2023, Angular 17 offers optimized performance enhancements, enabling you to craft high-performing web applications capable of meeting modern user expectations.
- Cutting-Edge Features: Stay ahead in the web development landscape by mastering the latest built-in control flows, deferrable views, and other advanced functionalities unique to Angular 17.
- Industry Relevance: With Angular continuing to be a sought-after framework in the industry, mastering Angular 17 ensures you remain competitive and relevant in the job market.
- Improved Developer Experience: Angular 17 introduces refinements and enhancements that streamline the development process, providing a more efficient and enjoyable experience for developers.
- Scalability and Maintainability: Learning Angular 17 equips you with the knowledge to build scalable and maintainable applications, crucial factors in modern software development.

### Why Learn Angular 17 in 2023

Angular 17 stands at the forefront of web development frameworks in the current year, offering you several compelling reasons to dive into its intricacies:
Embrace the evolution of web development by mastering Angular 17 in 2023. This advanced version presents you with enhanced performance capabilities, cutting-edge features, and improved developer experiences. Remaining proficient in Angular ensures your relevance in a competitive industry, equipping you with the skills necessary to build scalable, high-performing applications that meet the demands of modern users.

### Course Content Overview

Course Overview:
Total Modules: **5**
Total Lessons: **12**
Total Video Runtime: **1 hour, 41 minutes**

### Summary:
This course is structured into five comprehensive modules, guiding you through the intricacies of Angular 17 Signals. From laying the groundwork with introductory concepts to diving deep into handling HTTP requests, sharing data between components, and culminating with a thorough review in the conclusion module, each section builds upon the last, empowering you to master Angular 17 Signals effectively.

Learn how to surgically manage state and optimize UI rendering with Angular Signals. This course introduces students to the world of Angular Signals, from reactive primitives to seamless interoperability between observables and signals. By the end of this course, you'll have learned how to build a highly performant, lightweight Angular application that features deferrable views, lazy loaded routes, and a PayPal-powered checkout flow. Additionally, you'll have learned the techniques needed to modernize older Angular applications so that they're able to fully leverage the power of Angular Signals.

Demystifying Reactivity with Angular Signals

Fetch data from a REST API making use of Signals.

Make use signals to add functionalities to the shopping cart

Checkout selected items from the cart using the available Signal APIs

How to manage state in an Angular application by making use of Signals

The importance of using Signals to enhance change detection

How to integrate a robust lazy loading approach, by making use of deferrable views and lazy loaded routes

Difference between using RxJS and Signals when working with data and asynchronous operations

How to structure an Angular application using Standalone components

How to work with the newly built-in control flows

Implementing Data Prefetching and Cart Functionality in Angular

This guide discusses how to enhance an Angular application by implementing data prefetching and adding items to the shopping cart. The guide starts by utilizing deferrable views when a user first lands on the page, effectively prefetching data and displaying a loading spinner as the data is fetched from the backend. Next, it delves into adding an 'add to cart' feature, which allows users to select items they want to purchase.

Data prefetching is an important aspect of user experience. It gives users immediate feedback that their request is being processed, which is particularly useful when data fetching may take some time. In this case, a spinner is shown on the page while the data is being fetched.

To implement data prefetching, navigate to the product components file and at the top, wrap the entire codebase with the 

 block to set a minimum time for the spinner to display - for this purpose, it is set to one second.

Here's a code snippet showing how to implement this:

@defabblock
{
    @loadingblock(1)
    {
        // Rest of the code...
    }
}

Now, let's add the functionality for users to add items to their shopping cart. Start by creating a method in the product component file. This function takes in a product of type 

 and logs the selected products when the user clicks on them.

Here's an example of how to implement that:

---
title: Adding Items to the Shopping Cart
description: In this module, we get to display how to spread data across different components with the use of Signals.
code: https://gitlab.com/fullstackio/books/newline-course-apps/fundamentals-of-signals-in-angular-app/-/tree/main/module_4?ref_type=heads
privateVideoUrl: https://stream.mux.com/vpQwdK1ZfJ9EGoYcouuqfIxvLpWtacs8rrc6W02D00Yzk.m3u8
isPublicLesson: true
---

# Implementing Data Prefetching and Cart Functionality in Angular

## Introduction

This guide discusses how to enhance an Angular application by implementing data prefetching and adding items to the shopping cart. The guide starts by utilizing deferrable views when a user first lands on the page, effectively prefetching data and displaying a loading spinner as the data is fetched from the backend. Next, it delves into adding an 'add to cart' feature, which allows users to select items they want to purchase.

## Data Prefetching

Data prefetching is an important aspect of user experience. It gives users immediate feedback that their request is being processed, which is particularly useful when data fetching may take some time. In this case, a spinner is shown on the page while the data is being fetched.

To implement data prefetching, navigate to the product components file and at the top, wrap the entire codebase with the `@defer` block. Then, use `@loading` block to set a minimum time for the spinner to display - for this purpose, it is set to one second.

deji adesoga

Before we get started with the functionality of this lesson, which is to add

shopping cuts, I would like also to take advantage and utilize with the defer

comes to the page for the first time, we'll get to utilize data prefetching by

a spinner on the page while the data is being fetched from the backend. To do

we'll switch to the product components file and then right at the top, we can

add the fab block to utilize these. So we wrap around the entire code base with

block and then call the add loading block sets a minimum time in which the spin

going to say this to one second and then I'm going to open bracket and then we

create a div. I would need this div as well as a class of loading and then we

then make use of some special characters and then save every time we've done so

The spinner is configured in our product components CSS file and the code base

for you to download in this lesson. Now that that is done, if I add back to the

we get to see the spinner while the data is being prefished. If I load the page

see the beautiful spinner right there. We're able to make use of the deferable

data for the user. Now we can go ahead to integrate the add to cut

add in straight to the product components. And I'm going to add to the product

We need to create a method or a function as my colleague that will create a

add items to add and then now call the method itself add to cut and then is

a product of type products. And within that, let's also log whatever products

clicks on any of the products. We need to import the product interface to get

Adding straight to the product component HTML file. We need to create a click

For any time the user clicks on this plus icon to write within this span tag, I

a click event. And then we're going to upload the function we created in a TS

the product to be conceived every time we've done so far. A straight to the

open up the console. And we did the console. We cannot test this out by

product. So I want to click the first product here. And as you can see, we have

that product displaying on the browser. As you can see, the title is so far for

And then the price is set as 50 USD. If I click on other products, probably the

we have right there, you can see we have the same data, which is wooden table.

set as 50 USD. Now we need to create a method in our service file was to

integration. So quickly, let's add to our product service file. And within the

we need to create a signal that helps us to undo the initial value of our

mean by this? This particular variable is going to hold all the values of the

and now browser. So we can just say cut items. And then we're gonna call it, we

it to a signal and then set the initial value. If I will do that, let's import

angular or slash call to get rid of any form of error. Or we need to still

variable because the signal was taking an initial variable. So this is where

come into play. I'm just gonna update in these values. And as I can see, what

is that if look out storage is equals to null, then it should return an mtr a

the value inside of lookout storage. So our initial value of our signal is

or if they if it's on mtr a then we're going to get any items selected from the

we need to create the methods to add item in our service file. So right below

console, I can just say add items to cuts. And then I'm gonna assign it to the

products. And then we can see is dot cards items. That is the items that are

updates, which is one of the methods available in signals. When you start to

an like it's dots, you can see we have sets, which is also one of the methods

updates previously in vice-class, it's thin of angular. We also add the meat

what it was dropped. So we're gonna make use of the updates. And then it's

and we're going to assign it a variable called val. And then I'm gonna create a

a square bracket to the level is to make use of the spread of pre-talk to