231 lines
10 KiB
Markdown
231 lines
10 KiB
Markdown
|
---
|
||
|
title: Angular 2 Starter Project
|
||
|
---
|
||
|
This tutorial will build an extremely simple seed project with Angular2\. We will begin with the most basic application possible and then add on a bit more functionality.
|
||
|
|
||
|
## Overview
|
||
|
|
||
|
Angular 2 applications are built by creating HTML templates that contain angular specific markup. Classes are then created to manage the templates and everything is wrapped into a module, which you piece together to create your application. These modules are referred to as **components**.
|
||
|
|
||
|
Angular interprets these modules and uses them to present your application in the browser.
|
||
|
|
||
|
## Starter Application
|
||
|
|
||
|
Let's get started with a minimal application. We will begin with an application that contains a single module whose only job is to display some text.
|
||
|
|
||
|
We will begin by creating a new folder called "app".
|
||
|
|
||
|
$ mkdir app
|
||
|
|
||
|
As mentioned above, our application will begin with a single module, or **component**, that will display some text to the screen. We can use both pure JavaScript or TypeScript to make an angular 2 app. Using TypeScript, it is easier and more programmer friendly ![:wink:](//forum.freecodecamp.com/images/emoji/emoji_one/wink.png?v=2 ":wink:")
|
||
|
|
||
|
Let's learn how to create a component using TypeScript.
|
||
|
|
||
|
Create a file called _`app.component.ts`_ as shown:
|
||
|
|
||
|
// app.component.ts
|
||
|
|
||
|
import { Component } from '@angular/core';
|
||
|
@Component({
|
||
|
selector: 'my-app',
|
||
|
template: '<h1>Free Code Camp Rocks!</h1>',
|
||
|
styles: <a href='http://plnkr.co/edit/BdvNONEmO3Jwg0EavX22' target='_blank' rel='nofollow'>`
|
||
|
h1 { color: darkgreen; font-family: Arial, Helvetica, sans-serif;}
|
||
|
`]
|
||
|
})
|
||
|
export class AppComponent { }
|
||
|
|
||
|
Every Angular 2 application has at least one component which is usually named **AppComponent**. A component manages a portion of the page using the template within it.
|
||
|
|
||
|
Our component demonstrates the basic structure of any component you will ever write. It contains:
|
||
|
* **import statements** to pull in other components we will need
|
||
|
* **component decorator** which lets angular know which template to use and how the component will be created. Basically, any meta data related to the component.
|
||
|
* **component class** which controls the component's appearance and behavior
|
||
|
|
||
|
Let's take a closer look at each line in our component.
|
||
|
|
||
|
## Import
|
||
|
|
||
|
import { Component } from '@angular/core';
|
||
|
|
||
|
Since angular applications are modular, we can import any other modules or libraries we may need. Here, we are importing the Angular 2 core module to give our component access to the `@Component` decorator. Every app will need this import to get started.
|
||
|
|
||
|
Since we imported the `Component` function above, we can now use it to associate metadata with our component class that will tell Angular how our component should be created and the actions it will provide.
|
||
|
|
||
|
## Component decorator
|
||
|
|
||
|
@Component({
|
||
|
selector: 'my-app',
|
||
|
template: '<h1>Free Code Camp Rocks!</h1>'
|
||
|
})
|
||
|
```
|
||
|
Our metadata object has selector and template fields.
|
||
|
* The `selector` specifies a CSS selector that indicates which HTML element will represent this component. The element we will use will be named "`my-app`". Angular will use this to create an instance of our component where it finds this element.
|
||
|
* The `template` tells angular what template it will use for this component. This can refer to other Components or just a form of HTML that tells how to display the view for our component. Our template is just displaying an `h1` element containing the text "`Free Code Camp Rocks!`".
|
||
|
|
||
|
## Component Class
|
||
|
Our final line provides an empty class named ***AppComponent***
|
||
|
```js
|
||
|
export class AppComponent { }
|
||
|
```
|
||
|
If we want to build a more complex component we can add logic and properties to the class. This component is extremely basic and simply displays some html, so its class will remain empty.
|
||
|
|
||
|
We export our class so we can use it in other components in our application.
|
||
|
|
||
|
Next, we need to connect our root component to Angular. To do this we create another file in our app folder called *`main.ts`* that will have the following code:
|
||
|
```js
|
||
|
import { bootstrap } from '@angular/platform-browser-dynamic';
|
||
|
import { AppComponent } from './app.component';
|
||
|
bootstrap(AppComponent);
|
||
|
```
|
||
|
This file imports the two items we need to start our app.
|
||
|
* **`bootstrap`** - Angular's built in method that connects to the browser
|
||
|
* **`AppComponent`** - Our component we created above (which is why we exported it)
|
||
|
We then call `bootstrap` method with `AppComponent`
|
||
|
|
||
|
**Finally, create index.html**
|
||
|
|
||
|
```html
|
||
|
<html>
|
||
|
<head>
|
||
|
<title>Free Code Camp - Angular 2 Tutorial</title>
|
||
|
<meta charset="UTF-8">
|
||
|
<meta name="viewport" content="width=device-width, initial-scale=1">
|
||
|
<link rel="stylesheet" href="styles.css">
|
||
|
<!-- 1\. Load libraries -->
|
||
|
<script src="https://npmcdn.com/core-js/client/shim.min.js"></script>
|
||
|
|
||
|
<script src="https://npmcdn.com/zone.js@0.6.12?main=browser"></script>
|
||
|
<script src="https://npmcdn.com/reflect-metadata@0.1.3"></script>
|
||
|
<script src="https://npmcdn.com/systemjs@0.19.27/dist/system.src.js"></script>
|
||
|
|
||
|
<!-- 2\. Configure SystemJS -->
|
||
|
<script src="systemjs.config.js"></script>
|
||
|
<script>
|
||
|
System.import('app').catch(function(err){ console.error(err); });
|
||
|
</script>
|
||
|
</head>
|
||
|
|
||
|
<!-- Display app in my-app element -->
|
||
|
<body>
|
||
|
<my-app>Loading Your App...</my-app>
|
||
|
</body>
|
||
|
</html>
|
||
|
```
|
||
|
In commented section 1, we loaded several libraries that improve the compatibility of this tutorial with different browsers/versions. It also imports `system.src.js` which is used as module loader to import the app.
|
||
|
|
||
|
In section 2, SystemJS is used to load our application and our various modules. In a production example we may want to use something else such as webpack. It was chosen here since we can use it with plunker.
|
||
|
|
||
|
This is all that is required to get our simple application running. <a href="http://plnkr.co/edit/2i7Wjwd2JGj4NZtKvGD2" target="_blank">Here is a link to a plunker</a> that contains our working application. You can fork it into your own version and change whatever you'd like.
|
||
|
|
||
|
<a target="_blank" href="http://plnkr.co/edit/2i7Wjwd2JGj4NZtKvGD2">VIEW APP</a>
|
||
|
|
||
|
## Add Functionality and Another Component
|
||
|
|
||
|
Now let's add a bit more functionality to our program. We will create a counter that let's you increment it by clicking a button.
|
||
|
|
||
|
Our increment component will be its own module so that we can reuse it in later applications.
|
||
|
|
||
|
Let's name our file: `app/increment-clicker.component.ts` and set it up.
|
||
|
```js
|
||
|
// app/increment-clicker.component.ts
|
||
|
import { Component } from '@angular/core';
|
||
|
|
||
|
@Component({
|
||
|
selector: 'increment-clicker',
|
||
|
template: `
|
||
|
<div className="counter">
|
||
|
<h1>{{curClicks}} clicks</h1>
|
||
|
<button type="button" (click)="incrementClicks()">Increment</button>
|
||
|
</div>
|
||
|
`,
|
||
|
styles: [`
|
||
|
.counter {
|
||
|
width: 100%;
|
||
|
margin: auto;
|
||
|
background: darkgreen;
|
||
|
border-radius: 5px;
|
||
|
color: white;
|
||
|
padding: 20px;
|
||
|
text-align: center;
|
||
|
}
|
||
|
.counter h1 {
|
||
|
margin: 0;
|
||
|
padding: 20px;
|
||
|
font-size: 36px;
|
||
|
}
|
||
|
.counter button {
|
||
|
background: #f1c40f;
|
||
|
border: 0;
|
||
|
box-shadow: 0px 5px 0px #927608;
|
||
|
padding: 20px;
|
||
|
width: 100%;
|
||
|
outline: none;
|
||
|
border-radius: 5px;
|
||
|
color: darkgreen;
|
||
|
font-weight: bold;
|
||
|
}
|
||
|
|
||
|
.counter button:hover {
|
||
|
background: #a9890a;
|
||
|
cursor: pointer;
|
||
|
}
|
||
|
`]
|
||
|
})
|
||
|
|
||
|
export class IncrementClicker {
|
||
|
curClicks = 0;
|
||
|
|
||
|
incrementClicks() {
|
||
|
this.curClicks++;
|
||
|
}
|
||
|
}
|
||
|
```
|
||
|
Our component structure is similar to our previous one, but we've added a bit of functionality here. You will notice our class is no longer empty. We've added a variable to track the clicks as well as a function to increment them when the user clicks the button.
|
||
|
|
||
|
You can display properties from your class in your template using double braces such as: `{{ variableName }}`
|
||
|
|
||
|
We bind the button click event to our class function using Angulars Event Bindings.
|
||
|
```html
|
||
|
<button type="button" (click)="incrementClicks()">Increment</button>
|
||
|
```
|
||
|
|
||
|
Notice that we've also added some styling to our components. This way everything is self-contained in this module. You may also include a `templateUrl` and/or `styleUrls` properties instead to extract the template and style rules to an external file and link them here.
|
||
|
|
||
|
Now we just need to update our `AppComponent` to include our new component:
|
||
|
```js
|
||
|
// app/app.component.ts
|
||
|
|
||
|
import { Component } from '@angular/core';
|
||
|
|
||
|
/* Nested Component */
|
||
|
import { IncrementClicker } from 'app/increment-clicker.component';
|
||
|
|
||
|
@Component({
|
||
|
selector: 'my-app',
|
||
|
directives: [IncrementClicker],
|
||
|
template: `
|
||
|
<h1>Free Code Camp Rocks!</h1>
|
||
|
<increment-clicker></increment-clicker>
|
||
|
`,
|
||
|
styles: [`
|
||
|
h1 { color: darkgreen; font-family: Arial, Helvetica, sans-serif;}
|
||
|
`]
|
||
|
})
|
||
|
|
||
|
export class AppComponent { }
|
||
|
```
|
||
|
To pull in our new `IncrementClicker` component we need to import it by including the class name as well as the location of the typescript file as we did on this line:
|
||
|
```js
|
||
|
import { IncrementClicker } from 'app/increment-clicker.component';
|
||
|
```
|
||
|
We then add the `IncrementClicker` *component* as a directive to the `AppComponent` module using:
|
||
|
```js
|
||
|
directives: [IncrementClicker],
|
||
|
|
||
|
Finally, we just add the tag that our component connects to in the template. So the selector in our `IncrementClicker` component will match the tag where we want it to show up.
|
||
|
`js
|
||
|
template: ` <h1>Free Code Camp Rocks!</h1> <increment-clicker></increment-clicker> `,`
|
||
|
Our component is now included in our app!
|
||
|
[Updated Code</a>
|
||
|
<a href='http://run.plnkr.co/plunks/BdvNONEmO3Jwg0EavX22/' target='_blank' rel='nofollow'>VIEW COMPLETE APPLICATION</a>
|