This tutorial introduces you to the essentials of Angular by walking you through building a simple e-commerce site with a catalog, shopping cart, and check-out form. It uses the [StackBlitz](https://stackblitz.com/ "StackBlitz website") online development environment so you can get started right away.
This guide uses the StackBlitz Generator to show you a ready-made, simple application that you can examine and play with interactively. In actual development you will typically use the [Angular CLI](guide/glossary#command-line-interface-cli), a powerful command-line tool that lets you generate and modify applications. For more information, see the [CLI Overview](cli).
There are many resources to complement the Angular docs. Mozilla's MDN docs include both [HTML](https://developer.mozilla.org/en-US/docs/Learn/HTML "Learning HTML: Guides and tutorials") and [JavaScript](https://developer.mozilla.org/en-US/docs/Web/JavaScript "JavaScript") introductions. [TypeScript's docs](https://www.typescriptlang.org/docs/home.html "TypeScript documentation") include a 5-minute tutorial. Various online course platforms, such as [Udemy](http://www.udemy.com "Udemy online courses") and [Codecademy](https://www.codecademy.com/ "Codeacademy online courses"), also cover web development basics.
1. Each product in the list displays the same way, one after another on the page. To iterate over the predefined list of products, put the `*ngFor` directive on a `<div>`, as follows:
`*ngFor` is a "structural directive". Structural directives shape or reshape the DOM's structure, typically by adding, removing, and manipulating the elements to which they are attached. Any directive with an asterisk, `*`, is a structural directive.
1. To display the names of the products, use the interpolation syntax `{{ }}`. Interpolation renders a property's value as text. Inside the `<div>`, add an `<h3>` to display the interpolation of the product's name property:
1. To make each product name a link to product details, add the `<a>` element and set its title to be the product's name by using the property binding `[ ]` syntax, as follows:
1. Add the product descriptions. On the `<p>` element, use an `*ngIf` directive so that Angular only creates the `<p>` element if the current product has a description.
The app now displays the name and description of each product in the list. Notice that the final product does not have a description paragraph. Because the product's description property is empty, Angular doesn't create the `<p>` element—including the word "Description".
1. Add a button so users can share a product with friends. Bind the button's `click` event to the `share()` method (in `product-list.component.ts`). Event binding uses a set of parentheses, `( )`, around the event, as in the following `<button>` element:
* **A component class** that handles data and functionality. In the previous section, the product data and the `share()` method in the component class handle data and functionality, respectively.
* **An HTML template** that determines the UI. In the previous section, the product list's HTML template displays the name, description, and a "Share" button for each product.
* **Component-specific styles** that define the look and feel.
Though product list does not define any styles, this is where component CSS
* The `selector` is used to identify the component. The selector is the name you give the Angular component when it is rendered as an HTML element on the page. By convention, Angular component selectors begin with the prefix such as `app-`, followed by the component name.
* The template and style filename also are provided here. By convention each of the component's parts is in a separate file, all in the same directory and with the same prefix.
1. The component definition also includes an exported class, which handles functionality for the component. This is where the product list data and `Share()` method are defined.
*`app-root` (orange box) is the application shell. This is the first component to load and the parent of all other components. You can think of it as the base page.
For more information about components and how they interact with templates, see [Introduction to Components](guide/architecture-components "Architecture > Introduction to Components").
The next step is to create a new alert feature that takes a product as an input. The alert checks the product's price, and, if the price is greater than $700, displays a "Notify Me" button that lets users sign up for notifications when the product goes on sale.
1. Notice the `@Component()` decorator. This indicates that the following class is a component. It provides metadata about the component, including its selector, templates, and styles.
* The `selector` identifies the component. The selector is the name you give the Angular component when it is rendered as an HTML element on the page. By convention, Angular component selectors begin with the prefix `app-`, followed by the component name.
1. In the `ProductAlertsComponent` class definition, define a property named `product` with an `@Input()` decorator. The `@Input()` decorator indicates that the property value passes in from the component's parent, the product list component.
1. Open the `product-alerts.component.html` template and replace the placeholder paragraph with a "Notify Me" button that appears if the product price is over $700.
The new product alert component takes a product as input from the product list. With that input, it shows or hides the "Notify Me" button, based on the price of the product. The Phone XL price is over $700, so the "Notify Me" button appears on that product.
See [Component Interaction](guide/component-interaction "Components & Templates > Component Interaction") for more information about passing data from a parent to child component, intercepting and acting upon a value from the parent, and detecting and acting on changes to input property values.
1. In the component class, define a property named `notify` with an `@Output()` decorator and an instance of `EventEmitter()`. This allows the product alert component to emit an event when the value of the notify property changes.
1. In the product alert template, `product-alerts.component.html`, update the "Notify Me" button with an event binding to call the `notify.emit()` method.
1. Next, define the behavior that should happen when the user clicks the button. Recall that it's the parent, product list component—not the product alerts component—that's acts when the child raises the event. In `product-list.component.ts`, define an `onNotify()` method, similar to the `share()` method:
In `product-list.component.html`, bind the `app-product-alerts` component (which is what displays the "Notify Me" button) to the `onNotify()` method of the product list component.
See [Component Interaction](guide/component-interaction "Components & Templates > Component Interaction") for more information about listening for events from child components, reading child properties or invoking child methods, and using a service for bi-directional communication between components.
* [Continue to the "Routing" section](start/routing "Getting Started: Routing") to create a product details page that can be accessed by clicking a product name and that has its own URL pattern.
* [Skip ahead to the "Deployment" section](start/deployment "Getting Started: Deployment") to move to local development, or deploy your app to Firebase or your own server.
