usefulfiles/cheatfiles/Aurelia.md

Aurelia Cheat Sheet

Configuration and Startup

Bootstrapping Older Browsers

    <script src="jspm_packages/system.js"></script>
    <script src="config.js"></script>
    <script>
      SystemJS.import('aurelia-polyfills').then(function() {
        return SystemJS.import('webcomponents/webcomponentsjs/MutationObserver');
      }).then(function() {
        SystemJS.import('aurelia-bootstrapper');
      });
    </script>

Warning: Promises in Edge Currently, the Edge browser has a serious performance problem with its Promise implementation. This deficiency can greatly increase startup time of your app. If you are targeting the Edge browser, it is highly recommended that you use the bluebird promise library to replace Edge's native implementation. You can do this by simply referencing the library prior to loading system.js.

Standard Startup Configuration

  export function configure(aurelia) {
    aurelia.use
      .standardConfiguration()
      .developmentLogging();

    aurelia.start().then(() => aurelia.setRoot());
  }

    import {Aurelia} from 'aurelia-framework';

    export function configure(aurelia: Aurelia): void {
      aurelia.use
        .standardConfiguration()
        .developmentLogging();

      aurelia.start().then(() => aurelia.setRoot());
    }

Explicit Startup Configuration

    import {LogManager} from 'aurelia-framework';
    import {ConsoleAppender} from 'aurelia-logging-console';

    LogManager.addAppender(new ConsoleAppender());
    LogManager.setLevel(LogManager.logLevel.debug);

    export function configure(aurelia) {
      aurelia.use
        .defaultBindingLanguage()
        .defaultResources()
        .history()
        .router()
        .eventAggregator();

      aurelia.start().then(() => aurelia.setRoot('app', document.body));
    }

---

  
    import {LogManager, Aurelia} from 'aurelia-framework';
    import {ConsoleAppender} from 'aurelia-logging-console';

    LogManager.addAppender(new ConsoleAppender());
    LogManager.setLevel(LogManager.logLevel.debug);

    export function configure(aurelia: Aurelia): void {
      aurelia.use
        .defaultBindingLanguage()
        .defaultResources()
        .history()
        .router()
        .eventAggregator();

      aurelia.start().then(() => aurelia.setRoot('app', document.body));
    }

Configuring A Feature

    export function configure(aurelia) {
      aurelia.use
        .standardConfiguration()
        .developmentLogging()
        .feature('feature-name', featureConfiguration);

      aurelia.start().then(() => aurelia.setRoot());
    }

---

    import {Aurelia} from 'aurelia-framework';

    export function configure(aurelia: Aurelia): void {
      aurelia.use
        .standardConfiguration()
        .developmentLogging()
        .feature('feature-name', featureConfiguration);

      aurelia.start().then(() => aurelia.setRoot());
    }

Installing a Plugin

    export function configure(aurelia) {
      aurelia.use
        .standardConfiguration()
        .developmentLogging()
        .plugin('plugin-name', pluginConfiguration);

      aurelia.start().then(() => aurelia.setRoot());
    }

---

    import {Aurelia} from 'aurelia-framework';

    export function configure(aurelia: Aurelia): void {
      aurelia.use
        .standardConfiguration()
        .developmentLogging()
        .plugin('plugin-name', pluginConfiguration);

      aurelia.start().then(() => aurelia.setRoot());
    }

Creating Components

UI components consist of two parts: a view-model and a view. Simply create each part in its own file. Use the same file name but different file extensions for the two parts. For example: hello${context.language.fileExtension} and hello.html.

Explicit Configuration

ES 2015

    import {useView, decorators} from 'aurelia-framework';

    export let Hello = decorators(useView('./hello.html')).on(class {
      ...
    });

ES 2016

    import {useView} from 'aurelia-framework';

    @useView('./hello.html')
    export class Hello {
      ...
    }

Typescript

    import {useView} from 'aurelia-framework';

    @useView('./hello.html')
    export class Hello {
      ...
    }

The Component Lifecycle

Components have a well-defined lifecycle:

1. constructor() - The view-model's constructor is called first.
2. created(owningView: View, myView: View) - If the view-model implements the created callback it is invoked next. At this point in time, the view has also been created and both the view-model and the view are connected to their controller. The created callback will receive the instance of the "owningView". This is the view that the component is declared inside of. If the component itself has a view, this will be passed second.
3. bind(bindingContext: Object, overrideContext: Object) - Databinding is then activated on the view and view-model. If the view-model has a bind callback, it will be invoked at this time. The "binding context" to which the component is being bound will be passed first. An "override context" will be passed second. The override context contains information used to traverse the parent hierarchy and can also be used to add any contextual properties that the component wants to add. It should be noted that when the view-model has implemented the bind callback, the databinding framework will not invoke the changed handlers for the view-model's bindable properties until the "next" time those properties are updated. If you need to perform specific post-processing on your bindable properties, when implementing the bind callback, you should do so manually within the callback itself.
4. attached() - Next, the component is attached to the DOM (in document). If the view-model has an attached callback, it will be invoked at this time.
5. detached() - At some point in the future, the component may be removed from the DOM. If/When this happens, and if the view-model has a detached callback, this is when it will be invoked.
6. unbind() - After a component is detached, it's usually unbound. If your view-model has the unbind callback, it will be invoked during this process.

Dependency Injection

import {inject} from 'aurelia-framework'; import {Dep1} from 'dep1'; import {Dep2} from 'dep2';

@inject(Dep1, Dep2)
export class CustomerDetail {
  constructor(dep1, dep2) {
    this.dep1 = dep1;
    this.dep2 = dep2;
  }
}

import {Dep1} from 'dep1'; import {Dep2} from 'dep2';

export class CustomerDetail {
  static inject() { return [Dep1, Dep2]; }

  constructor(dep1, dep2) {
    this.dep1 = dep1;
    this.dep2 = dep2;
  }
}

import {autoinject} from 'aurelia-framework'; import {Dep1} from 'dep1'; import {Dep2} from 'dep2';

@autoinject
export class CustomerDetail {
  constructor(private dep1: Dep1, private dep2: Dep2){ }
}

import {Lazy, inject} from 'aurelia-framework'; import {HttpClient} from 'aurelia-fetch-client';

@inject(Lazy.of(HttpClient))
export class CustomerDetail {
  constructor(getHTTP){
    this.getHTTP = getHTTP;
  }
}

import {Lazy} from 'aurelia-framework'; import {HttpClient} from 'aurelia-fetch-client';

export class CustomerDetail {
  static inject() { return [Lazy.of(HttpClient)]; }

  constructor(getHTTP){
    this.getHTTP = getHTTP;
  }
}

import {Lazy, inject} from 'aurelia-framework'; import {HttpClient} from 'aurelia-fetch-client';

@inject(Lazy.of(HttpClient))
export class CustomerDetail {
  constructor(private getHTTP: () => HttpClient){ }
}

Available Resolvers

• Lazy - Injects a function for lazily evaluating the dependency.
  • ex. Lazy.of(HttpClient)
• All - Injects an array of all services registered with the provided key.
  • ex. All.of(Plugin)
• Optional - Injects an instance of a class only if it already exists in the container; null otherwise.
  • ex. Optional.of(LoggedInUser)
• Parent - Skips starting dependency resolution from the current container and instead begins the lookup process on the parent container.
  • ex. Parent.of(MyCustomElement)
• Factory - Used to allow injecting dependencies, but also passing data to the constructor.
  • ex. Factory.of(CustomClass)
• NewInstance - Used to inject a new instance of a dependency, without regard for existing instances in the container.
  • ex. NewInstance.of(CustomClass).as(Another)

import {transient, inject} from 'aurelia-framework'; import {HttpClient} from 'aurelia-fetch-client';

@transient()
@inject(HttpClient)
export class CustomerDetail {
  constructor(http) {
    this.http = http;
  }
}

import {transient, inject} from 'aurelia-framework'; import {HttpClient} from 'aurelia-fetch-client';

export let CustomDetail = decorators(
  transient()
  inject(HttpClient)
).on(class {
  constructor(http) {
    this.http = http;
  }
});

import {transient, autoinject} from 'aurelia-framework'; import {HttpClient} from 'aurelia-fetch-client';

@transient()
@autoinject
export class CustomerDetail {
  constructor(private http: HttpClient) { }
}

Templating Basics

Hello World!

  <nav-bar router.bind="router"></nav-bar>

  <div class="page-host">
    <router-view></router-view>
  </div>
</template>

Info: Invalid Table Structure When Dynamically Creating Tables When the browser loads in the template it very helpfully validates the structure of the HTML, notices that you have an invalid tag inside your table definition, and very unhelpfully removes it for you before Aurelia even has a chance to examine your template.

Use of the as-element attribute ensures we have a valid HTML table structure at load time, yet we tell Aurelia to treat its contents as though it were a different tag.

For the above example we can then programmatically choose the embedded template based on an element of our data:

I'm an A RowCol 2ACol 3A I'm an B RowCol 2BCol 3B

Note that when a containerless attribute is used, the container is stripped after the browser has loaded the DOM elements, and as such this method cannot be used to transform non-HTML compliant structures into compliant ones!

${customer.fullName}

${customer.fullName}

... ...

Databinding

bind, one-way, two-way & one-time

Use on any HTML attribute.

• .bind - Uses the default binding. One-way binding for everything but form controls, which use two-way binding.
• .one-way - Flows data one direction: from the view-model to the view.
• .two-way - Flows data both ways: from view-model to view and from view to view-model.
• .one-time - Renders data once, but does not synchronize changes after the initial render.

  <a href.one-way="profileUrl">View Profile</a>
</template>

Info At the moment inheritance of bindables is not supported. For use cases where class B extends A and B is used as custom Element/Attribute @bindable properties cannot be defined only on class A. If inheritance is used, @bindable properties should be defined on the instantiated class.

delegate, trigger

Use on any native or custom DOM event. (Do not include the "on" prefix in the event name.)

• .trigger - Attaches an event handler directly to the element. When the event fires, the expression will be invoked.
• .delegate - Attaches a single event handler to the document (or nearest shadow DOM boundary) which handles all events of the specified type, properly dispatching them back to their original targets for invocation of the associated expression.

Info The $event value can be passed as an argument to a delegate or trigger function call if you need to access the event object.

Save Save

call

Passes a function reference.

Say Hello

ref

Creates a reference to an HTML element, a component or a component's parts.

• ref="someIdentifier" or element.ref="someIdentifier" - Create a reference to the HTMLElement in the DOM.
• attribute-name.ref="someIdentifier"- Create a reference to a custom attribute's view-model.
• view-model.ref="someIdentifier"- Create a reference to a custom element's view-model.
• view.ref="someIdentifier"- Create a reference to a custom element's view instance (not an HTML Element).
• controller.ref="someIdentifier"- Create a reference to a custom element's controller instance.

${name.value}

String Interpolation

Used in an element's content. Can be used inside attributes, particularly useful in the class and css attributes.

${fullName}

Binding to Select Elements

A typical select element is rendered using a combination of value.bind and repeat. You can also bind to arrays of objects and synchronize based on an id (or similar) property.

Select A Color ${color} Select An Employee ${employee.fullName} Select An Employee ${employee.fullName} ${color} ${employee.fullName}

Binding Radios

${color} ${employee.fullName} Unanswered Yes No

Binding Checkboxes

Warning You cannot use a click.delegate on checkboxes if you want to attach a method to it. You need to use change.delegate.

${color} ${employee.fullName}

Fudge

Sprinkles

Cherry

Binding innerHTML and textContent

Danger Always use HTML sanitization. We provide a simple converter that can be used. You are encouraged to use a more complete HTML sanitizer such as sanitize-html.

Warning Binding using the innerhtml attribute simply sets the element's innerHTML property. The markup does not pass through Aurelia's templating system. Binding expressions and require elements will not be evaluated.

Binding Style

You can bind a css string or object to an element's style attribute. Use the style attribute's alias, css when doing string interpolation to ensure your application is compatible with Internet Explorer.

export class StyleData { constructor() { this.styleString = 'color: red; background-color: blue';

    this.styleObject = {
      color: 'red',
      'background-color': 'blue'
    };
  }
}

export class StyleData { styleString: string; styleObject: any;

  constructor() {
    this.styleString = 'color: red; background-color: blue';

    this.styleObject = {
      color: 'red',
      'background-color': 'blue'
    };
  }
}

Declaring Computed Property Dependencies

import {declarePropertyDependencies} from 'aurelia-framework';

export class Person {
  firstName = 'John';
  lastName = 'Doe';

  get fullName(){
    return `${this.firstName} ${this.lastName}`;
  }
}

declarePropertyDependencies(Person, 'fullName', ['firstName', 'lastName']);

import {computedFrom} from 'aurelia-framework';

export class Person {
  firstName = 'John';
  lastName = 'Doe';

  @computedFrom('firstName', 'lastName')
  get fullName(){
    return `${this.firstName} ${this.lastName}`;
  }
}

import {computedFrom} from 'aurelia-framework';

export class Person {
  firstName: string = 'John';
  lastName: string = 'Doe';

  @computedFrom('firstName', 'lastName')
  get fullName(): string {
    return `${this.firstName} ${this.lastName}`;
  }
}

Templating View Resources

  <template if.bind="hasErrors">
      <i class="icon error"></i>
      ${errorMessage}
  </template>
</template>

• ${customer.fullName}

• ${id} ${customer.fullName}

• *

Contextual items available inside a repeat template:

• $index - The index of the item in the array.
• $first - True if the item is the first item in the array.
• $last - True if the item is the last item in the array.
• $even - True if the item has an even numbered index.
• $odd - True if the item has an odd numbered index.

Info: Containerless Template Controllers The if and repeat attributes are usually placed on the HTML elements that they affect. However, you can also use a template tag to group a collection of elements that don't have a parent element and place the if or repeat on the template element instead.

Routing

export class App { configureRouter(config, router) { this.router = router; config.title = 'Aurelia'; config.map([ { route: ['', 'home'], name: 'home', moduleId: 'home/index' }, { route: 'users', name: 'users', moduleId: 'users/index', nav: true }, { route: 'users/:id/detail', name: 'userDetail', moduleId: 'users/detail' }, { route: 'files*path', name: 'files', moduleId: 'files/index', href:'#files', nav: true } ]); } } import {RouterConfiguration, Router} from 'aurelia-router';

export class App {
  configureRouter(config: RouterConfiguration, router: Router): void {
    this.router = router;
    config.title = 'Aurelia';
    config.map([
      { route: ['', 'home'],       name: 'home',       moduleId: 'home/index' },
      { route: 'users',            name: 'users',      moduleId: 'users/index',   nav: true },
      { route: 'users/:id/detail', name: 'userDetail', moduleId: 'users/detail' },
      { route: 'files*path',       name: 'files',      moduleId: 'files/index',   href:'#files',   nav: true }
    ]);
  }
}

Route Pattern Options

• static routes
  • ie 'home' - Matches the string exactly.
• parameterized routes
  • ie 'users/:id/detail' - Matches the string and then parses an id parameter. Your view-model's activate callback will be called with an object that has an id property set to the value that was extracted from the url.
• wildcard routes
  • ie 'files*path' - Matches the string and then anything that follows it. Your view-model's activate callback will be called with an object that has a path property set to the wildcard's value.

The Route Screen Activation Lifecycle

• canActivate(params, routeConfig, navigationInstruction) - Implement this hook if you want to control whether or not your view-model can be navigated to. Return a boolean value, a promise for a boolean value, or a navigation command.
• activate(params, routeConfig, navigationInstruction) - Implement this hook if you want to perform custom logic just before your view-model is displayed. You can optionally return a promise to tell the router to wait to bind and attach the view until after you finish your work.
• canDeactivate() - Implement this hook if you want to control whether or not the router can navigate away from your view-model when moving to a new route. Return a boolean value, a promise for a boolean value, or a navigation command.
• deactivate() - Implement this hook if you want to perform custom logic when your view-model is being navigated away from. You can optionally return a promise to tell the router to wait until after you finish your work.

Warning: Root Screen Activation Unlike the mapped routes, the root's view-model only has access to the activate() hook. However this can also be used to implement logic for attaching the component by returning a promise for a boolean value.

The params object will have a property for each parameter of the route that was parsed, as well as a property for each query string value. routeConfig will be the original route configuration object that you set up. routeConfig will also have a new navModel property, which can be used to change the document title for data loaded by your view-model. For example:

import {autoinject} from 'aurelia-framework'; import {UserService} from './user-service';

@inject(UserService)
export class UserEditScreen {
  constructor(userService) {
    this.userService = userService;
  }

  activate(params, routeConfig) {
    return this.userService.getUser(params.id)
      .then(user => {
        routeConfig.navModel.setTitle(user.name);
      });
  }
}

import {UserService} from './user-service';

export class UserEditScreen {
  static inject() { return [UserService]; }

  constructor(userService) {
    this.userService = userService;
  }

  activate(params, routeConfig) {
    return this.userService.getUser(params.id)
      .then(user => {
        routeConfig.navModel.setTitle(user.name);
      });
  }
}

import {autoinject} from 'aurelia-framework'; import {RouteConfig} from 'aurelia-router'; import {UserService} from './user-service';

@autoinject
export class UserEditScreen {
  constructor(userService: UserService) { }

  activate(params: any, routeConfig: RouteConfig): Promise<any> {
    return this.userService.getUser(params.id)
      .then(user => {
        routeConfig.navModel.setTitle(user.name);
      });
  }
}

export class App { configureRouter(config){ config.mapUnknownRoutes(instruction => { //check instruction.fragment //return moduleId }); } } import {RouterConfiguration} from 'aurelia-router';

export class App {
  configureRouter(config: RouterConfiguration): void {
    config.mapUnknownRoutes(instruction => {
      //check instruction.fragment
      //return moduleId
    });
  }
}

import {Redirect} from 'aurelia-router';

export class App {
  configureRouter(config) {
    config.title = 'Aurelia';
    config.addPipelineStep('authorize', AuthorizeStep);
    config.map([
      { route: ['welcome'],    name: 'welcome',       moduleId: 'welcome',      nav: true, title:'Welcome' },
      { route: 'flickr',       name: 'flickr',        moduleId: 'flickr',       nav: true, auth: true },
      { route: 'child-router', name: 'childRouter',   moduleId: 'child-router', nav: true, title:'Child Router' },
      { route: '', redirect: 'welcome' }
    ]);
  }
}

class AuthorizeStep {
  run(navigationInstruction, next) {
    if (navigationInstruction.getAllInstructions().some(i => i.config.auth)) {
      var isLoggedIn = /* insert magic here */false;
      if (!isLoggedIn) {
        return next.cancel(new Redirect('login'));
      }
    }

    return next();
  }
}

import {Redirect, NavigationInstruction, RouterConfiguration, Next} from 'aurelia-router';

export class App {
  configureRouter(config: RouterConfiguration): void {
    config.title = 'Aurelia';
    config.addPipelineStep('authorize', AuthorizeStep);
    config.map([
      { route: ['welcome'],    name: 'welcome',       moduleId: 'welcome',      nav: true, title:'Welcome' },
      { route: 'flickr',       name: 'flickr',        moduleId: 'flickr',       nav: true, auth: true },
      { route: 'child-router', name: 'childRouter',   moduleId: 'child-router', nav: true, title:'Child Router' },
      { route: '', redirect: 'welcome' }
    ]);
  }
}

class AuthorizeStep {
  run(navigationInstruction: NavigationInstruction, next: Next): Promise<any> {
    if (navigationInstruction.getAllInstructions().some(i => i.config.auth)) {
      var isLoggedIn = /* insert magic here */false;
      if (!isLoggedIn) {
        return next.cancel(new Redirect('login'));
      }
    }

    return next();
  }
}

Configuring PushState

Add a base tag to the head of your html document. If you're using JSPM, you will also need to configure it with a baseURL corresponding to your base tag's href. Finally, be sure to set the config.options.root to match your base tag's setting.

export class App { configureRouter(config) { config.title = 'Aurelia'; config.options.pushState = true; config.options.root = '/'; config.map([ { route: ['welcome'], name: 'welcome', moduleId: 'welcome', nav: true, title:'Welcome' }, { route: 'flickr', name: 'flickr', moduleId: 'flickr', nav: true, auth: true }, { route: 'child-router', name: 'childRouter', moduleId: 'child-router', nav: true, title:'Child Router' }, { route: '', redirect: 'welcome' } ]); } } import {Redirect, NavigationInstruction, RouterConfiguration} from 'aurelia-router';

export class App {
  configureRouter(config: RouterConfiguration): void {
    config.title = 'Aurelia';
    config.options.pushState = true;
    config.options.root = '/';
    config.map([
      { route: ['welcome'],    name: 'welcome',     moduleId: 'welcome',      nav: true, title:'Welcome' },
      { route: 'flickr',       name: 'flickr',      moduleId: 'flickr',       nav: true, auth: true },
      { route: 'child-router', name: 'childRouter', moduleId: 'child-router', nav: true, title:'Child Router' },
      { route: '',             redirect: 'welcome' }
    ]);
  }
}

Warning PushState requires server-side support. Don't forget to configure your server appropriately.

Reusing an existing VM

Since the VM's navigation life-cycle is called only once you may have problems recognizing that the user switched the route from Product A to Product B (see below). To work around this issue implement the method determineActivationStrategy in your VM and return hints for the router about what you'd like to happen.

Info Additionally, you can add an activationStrategy property to your route config if the strategy is always the same and you don't want that to be in your view-model code. Available values are replace and invoke-lifecycle. Remember, "lifecycle" refers to the navigation lifecycle.

//app.js

export class App {
  configureRouter(config) {
    config.title = 'Aurelia';
    config.map([
      { route: 'product/a',    moduleId: 'product',     nav: true },
      { route: 'product/b',    moduleId: 'product',     nav: true },
    ]);
  }
}

//product.js

import {activationStrategy} from 'aurelia-router';

export class Product {
  determineActivationStrategy(){
    return activationStrategy.replace;
  }
}

import {RouterConfiguration} from 'aurelia-router';

//app.ts

export class App {
  configureRouter(config: RouterConfiguration): void {
    config.title = 'Aurelia';
    config.map([
      { route: 'product/a',    moduleId: 'product',     nav: true },
      { route: 'product/b',    moduleId: 'product',     nav: true },
    ]);
  }
}

//product.ts

import {activationStrategy} from 'aurelia-router';

export class Product {
  determineActivationStrategy(): string {
    return activationStrategy.replace;
  }
}

Rendering multiple ViewPorts

Info If you don't name a router-view, it will be available under the name 'default'.

export class App { configureRouter(config){ config.map([{ route: 'edit', viewPorts: { left: { moduleId: 'editor' }, right: { moduleId: 'preview' } } }]); } } import {RouterConfiguration} from 'aurelia-router';

export class App {
  configureRouter(config: RouterConfiguration): void {
    config.map([{
      route: 'edit',
        viewPorts: {
          left: {
            moduleId: 'editor'
          },
          right: {
            moduleId: 'preview'
          }
        }
      }]);
  }
}

Generating Route URLs

router.generate('routeName', { id: 123 }); router.navigateToRoute('routeName', { id: 123 }) ${user.name}

Custom Attributes

import {inject, customAttribute, DOM} from 'aurelia-framework';

@customAttribute('my-attribute')
@inject(DOM.Element)
export class Show {
  constructor(element) {
    this.element = element;
  }

  valueChanged(newValue, oldValue) {
    ...
  }
}

import {customAttribute, inject, decorators} from 'aurelia-framework';

export let MyAttribute = decorators(
  customAttribute('my-attribute'),
  inject(DOM.Element)
).on(class {
  constructor(element) {
    this.element = element;
  }

  valueChanged(newValue, oldValue) {
    ...
  }
});

import {inject, customAttribute, DOM} from 'aurelia-framework';

@customAttribute('my-attribute')
@inject(DOM.Element)
export class Show {
  constructor(private element: Element) { }

  valueChanged(newValue, oldValue) {
    ...
  }
}

import {customAttribute, bindable} from 'aurelia-framework';

@customAttribute('my-attribute')
export class MyAttribute {
  @bindable foo;
  @bindable bar;

  fooChanged(newValue, oldValue) { ... }

  barChanged(newValue, oldValue) { ... }
}

import {customAttribute, bindable, decorators} from 'aurelia-framework';

export let MyAttribute = decorators(
  customAttribute('my-attribute'),
  bindable('foo'),
  bindable('bar')
).on(class {
  fooChanged(newValue, oldValue) { ... }

  barChanged(newValue, oldValue) { ... }
});

import {customAttribute, bindable} from 'aurelia-framework';

@customAttribute('my-attribute')
export class MyAttribute {
  @bindable foo: any;
  @bindable bar: any;

  fooChanged(newValue: any, oldValue: any): void { ... }

  barChanged(newValue: any, oldValue: any): void  { ... }
}

import {customAttribute, dynamicOptions} from 'aurelia-framework';

@customAttribute('my-attribute')
@dynamicOptions
export class MyAttribute {
  propertyChanged(propertyName, newValue, oldValue) { ... }
}

import {customAttribute, dynamicOptions, decorators} from 'aurelia-framework';

export let MyAttribute = decorators(
  customAttribute('my-attribute'),
  dynamicOptions()
).on(class {
  propertyChanged(propertyName, newValue, oldValue) { ... }
});

import {customAttribute, dynamicOptions} from 'aurelia-framework';

@customAttribute('my-attribute')
@dynamicOptions
export class MyAttribute {
  propertyChanged(propertyName: string, newValue: any, oldValue: any) { ... }
}

bindable({ name:'myProperty', attribute:'my-property', changeHandler:'myPropertyChanged', defaultBindingMode: bindingMode.oneWay, defaultValue: undefined }) import {BoundViewFactory, ViewSlot, customAttribute, templateController, inject} from 'aurelia-framework';

@customAttribute('naive-if')
@templateController
@inject(BoundViewFactory, ViewSlot)
export class NaiveIf {
  constructor(viewFactory, viewSlot) {
    this.viewFactory = viewFactory;
    this.viewSlot = viewSlot;
  }

  valueChanged(newValue) {
    if (newValue) {
      let view = this.viewFactory.create();
      this.viewSlot.add(view);
    } else {
      this.viewSlot.removeAll();
    }
  }
}

import {BoundViewFactory, ViewSlot, customAttribute, templateController, inject} from 'aurelia-framework';

export let MyAttribute = decorators(
  customAttribute('naive-if')
  templateController()
  inject(BoundViewFactory, ViewSlot)
).on(class {
  constructor(viewFactory, viewSlot) {
    this.viewFactory = viewFactory;
    this.viewSlot = viewSlot;
  }

  valueChanged(newValue) {
    if (newValue) {
      let view = this.viewFactory.create();
      this.viewSlot.add(view);
    } else {
      this.viewSlot.removeAll();
    }
  }
});

import {BoundViewFactory, ViewSlot, customAttribute, templateController, autoinject} from 'aurelia-framework';

@customAttribute('naive-if')
@templateController
@autoinject
export class NaiveIf {
  constructor(private viewFactory: BoundViewFactory, private viewSlot: ViewSlot) { }

  valueChanged(newValue: any): void {
    if (newValue) {
      let view = this.viewFactory.create();
      this.viewSlot.add(view);
    } else {
      this.viewSlot.removeAll();
    }
  }
}

  <template naive-if.bind="an.expression">
    <div></div>
    <div></div>
  </template>
</template>

Custom Elements

import {customElement, bindable} from 'aurelia-framework';

@customElement('say-hello')
export class SayHello {
  @bindable to;

  speak(){
    alert(`Hello ${this.to}!`);
  }
}

import {customElement, bindable} from 'aurelia-framework';

export let SayHello = decorators(
  customElement('say-hello'),
  bindable('to')
).on(class {
  speak(){
    alert(`Hello ${this.to}!`);
  }
});

import {customElement, bindable} from 'aurelia-framework';

@customElement('say-hello')
export class SayHello {
  @bindable to: string;

  speak(): void {
    alert(`Hello ${this.to}!`);
  }
}

Say Hello To ${to}

  <input type="text" ref="name">
  <say-hello to.bind="name.value"></say-hello>
</template>

Custom Element Without View-Model Declaration

Aurelia will not search for a JavaScript file if you reference a component with an .html extension.

Say ${greeting} To ${name} aurelia.use.globalResources('./js-less-component.html');

<js-less-component greeting="Hello" name.bind="someProperty"></js-less-component>

Custom Element Variable Binding

It's worth noting that when binding variables to custom elements, use camelCase inside the custom element's View-Model, and dash-case on the html element. See the following example:

import {bindable} from 'aurelia-framework';

export class SayHello {
  @bindable to;
  @bindable greetingCallback;

  speak(){
    this.greetingCallback(`Hello ${this.to}!`);
  }
}

import {bindable} from 'aurelia-framework';

export let SayHello = decorators(
  bindable('to'),
  bindable('greetingCallback')
).on(class {
  speak(){
    this.greetingCallback(`Hello ${this.to}!`);
  }
});

import {bindable} from 'aurelia-framework';

export class SayHello {
  @bindable to: string;
  @bindable greetingCallback: Function;

  speak(): void {
    this.greetingCallback(`Hello ${this.to}!`);
  }
}

  <input type="text" ref="name">
  <say-hello to.bind="name.value" greeting-callback.call="doSomething($event)"></say-hello>
</template>

Custom Element Options

• @children(selector) - Decorates a property to create an array on your class that has its items automatically synchronized based on a query selector against the element's immediate child content.
• @child(selector) - Decorates a property to create a reference to a single immediate child content element.
• @processContent(false|Function) - Tells the compiler that the element's content requires special processing. If you provide false to the decorator, the compiler will not process the content of your custom element. It is expected that you will do custom processing yourself. But, you can also supply a custom function that lets you process the content during the view's compilation. That function can then return true/false to indicate whether or not the compiler should also process the content. The function takes the following form function(compiler, resources, node, instruction):boolean
• @useView(path) - Specifies a different view to use.
• @noView() - Indicates that this custom element does not have a view and that the author intends for the element to handle its own rendering internally.
• @inlineView(markup, dependencies?) - Allows the developer to provide a string that will be compiled into the view.
• @useShadowDOM() - Causes the view to be rendered in the ShadowDOM. When an element is rendered to ShadowDOM, a special DOMBoundary instance can optionally be injected into the constructor. This represents the shadow root.
• @containerless() - Causes the element's view to be rendered without the custom element container wrapping it. This cannot be used in conjunction with @child, @children or @useShadowDOM decorators. It also cannot be uses with surrogate behaviors. Use sparingly.

SVG Elements

SVG (scalable vector graphic) tags can support Aurelia's custom element <template> tags by nesting the templated code inside a second <svg> tag. For example if you had a base <svg> element and wanted to add a templated <rect> inside it, you would first put your custom tag inside the main <svg> tag. Also, make sure the custom element class uses the @containerless() decorator.

import {containerless} from 'aurelia-framework';

@containerless()
export class MyCustomRect {
	...
}

import {containerless} from 'aurelia-framework';

export let MyCustomRect = decorators(
  containerless()
).on(class {
  ...
});

import {containerless} from 'aurelia-framework';

@containerless()
export class MyCustomRect {
	...
}

	<svg width="100" height="100" >
		<my-custom-rect></my-custom-rect>
	</svg>
</template>

Template Parts

• Original: ${item}

  <my-element>
    <template replace-part="item-template">
      Replacement: ${item}
    </template>
  </my-element>
</template>

Observable decorator

Aurelia exposes a decorator named observable to allow watching for changes to a property and reacting to them. By convention it will look for a matching method name ${name}Changed -

import {observable} from 'aurelia-framework';

export class MyCustomViewModel {
  @observable name = 'Hello world';
  nameChanged(newValue, oldValue) {
    // react to change
  }
}

import {decorators, observable} from 'aurelia-framework';

export let MyCustomViewModel = decorators(
  observable('name')
).on(class {
  nameChanged(newValue, oldValue) {
    // react to change
  }
});

import {observable} from 'aurelia-framework';

export class MyCustomViewModel {
  @observable name = 'Hello world';
  nameChanged(newValue, oldValue) {
    // react to change
  }
}

The developer can also specify a different method name to use -

import {observable} from 'aurelia-framework';

export class MyCustomViewModel {
  @observable({changeHandler: 'nameChanged'}) name = 'Hello world';
  nameChanged(newValue, oldValue) {
    // react to change
  }
}

import {decorators, observable} from 'aurelia-framework';

export let MyCustomViewModel = decorators(
  observable({name:'name', changeHandler: 'nameChanged'})
).on(class {
  nameChanged(newValue, oldValue) {
    // react to change
  }
});

import {observable} from 'aurelia-framework';

export class MyCustomViewModel {
  @observable({changeHandler: 'nameChanged'}) name = 'Hello world';
  nameChanged(newValue, oldValue) {
    // react to change
  }
}

The Event Aggregator

If you include the aurelia-event-aggregator plugin using "basicConfiguration" or "standardConfiguration" then the singleton EventAggregator's API will be also present on the Aurelia object. You can also create additional instances of the EventAggregator, if needed, and "merge" them into any object. To do this, import includeEventsIn and invoke it with the object you wish to turn into an event aggregator. For example includeEventsIn(myObject). Now my object has publish and subscribe methods and can be used in the same way as the global event aggregator, detailed below.

import {inject} from 'aurelia-framework'; import {EventAggregator} from 'aurelia-event-aggregator';

@inject(EventAggregator)
export class APublisher {
  constructor(eventAggregator) {
    this.eventAggregator = eventAggregator;
  }

  publish(){
    var payload = {};
    this.eventAggregator.publish('channel name here', payload);
  }
}

import {EventAggregator} from 'aurelia-event-aggregator';

export class APublisher{
  static inject() { return [EventAggregator]; }

  constructor(eventAggregator){
    this.eventAggregator = eventAggregator;
  }

  publish(){
    var payload = {};
    this.eventAggregator.publish('channel name here', payload);
  }
}

import {autoinject} from 'aurelia-framework'; import {EventAggregator} from 'aurelia-event-aggregator';

@autoinject
export class APublisher {
  constructor(private eventAggregator: EventAggregator) { }

  publish(): void {
    var payload = {};
    this.eventAggregator.publish('channel name here', payload);
  }
}

import {inject} from 'aurelia-framework'; import {EventAggregator} from 'aurelia-event-aggregator';

@inject(EventAggregator)
export class ASubscriber {
  constructor(eventAggregator) {
    this.eventAggregator = eventAggregator;
  }

  subscribe() {
    this.eventAggregator.subscribe('channel name here', payload => {
        ...
    });
  }
}

import {EventAggregator} from 'aurelia-event-aggregator';

export class ASubscriber {
  static inject() { return [EventAggregator]; }

  constructor(eventAggregator) {
    this.eventAggregator = eventAggregator;
  }

  subscribe() {
    this.eventAggregator.subscribe('channel name here', payload => {
        ...
    });
  }
}

import {autoinject} from 'aurelia-framework'; import {EventAggregator} from 'aurelia-event-aggregator';

@autoinject
export class ASubscriber {
  constructor(private eventAggregator: EventAggregator) { }

  subscribe(): void {
    this.eventAggregator.subscribe('channel name here', payload => {
        ...
    });
  }
}

//some-message.js export class SomeMessage{ }

//a-publisher.js
import {inject} from 'aurelia-framework';
import {EventAggregator} from 'aurelia-event-aggregator';
import {SomeMessage} from './some-message';

@inject(EventAggregator)
export class APublisher {
  constructor(eventAggregator) {
    this.eventAggregator = eventAggregator;
  }

  publish() {
    this.eventAggregator.publish(new SomeMessage());
  }
}

//some-message.js export class SomeMessage{ }

//a-publisher.js
import {EventAggregator} from 'aurelia-event-aggregator';
import {SomeMessage} from './some-message';

export class APublisher {
  static inject() { return [EventAggregator] };

  constructor(eventAggregator) {
    this.eventAggregator = eventAggregator;
  }

  publish() {
    this.eventAggregator.publish(new SomeMessage());
  }
}

//some-message.ts export class SomeMessage{ }

//a-publisher.ts
import {autoinject} from 'aurelia-framework';
import {EventAggregator} from 'aurelia-event-aggregator';
import {SomeMessage} from './some-message';

@autoinject
export class APublisher {
  constructor(private eventAggregator: EventAggregator) { }

  publish(): void {
    this.eventAggregator.publish(new SomeMessage());
  }
}

import {inject} from 'aurelia-framework'; import {EventAggregator} from 'aurelia-event-aggregator'; import {SomeMessage} from './some-message';

@inject(EventAggregator)
export class ASubscriber {
  constructor(eventAggregator) {
    this.eventAggregator = eventAggregator;
  }

  subscribe(){
    this.eventAggregator.subscribe(SomeMessage, message => {
        ...
    });
  }
}

import {EventAggregator} from 'aurelia-event-aggregator'; import {SomeMessage} from './some-message';

export class ASubscriber {
  static inject() { return [EventAggregator]; }

  constructor(eventAggregator) {
    this.eventAggregator = eventAggregator;
  }

  subscribe(){
    this.eventAggregator.subscribe(SomeMessage, message => {
        ...
    });
  }
}

import {autoinject} from 'aurelia-framework'; import {EventAggregator} from 'aurelia-event-aggregator'; import {SomeMessage} from './some-message';

@autoinject
export class ASubscriber {
  constructor(private eventAggregator: EventAggregator) { }

  subscribe(): void {
    this.eventAggregator.subscribe(SomeMessage, message => {
        ...
    });
  }
}