Dialog

The basics of the dialog plugin for Aurelia.

Introduction
This article covers the dialog plugin for Aurelia. This plugin is created for showing dialogs (sometimes referred to as modals) in our application. The plugin supports the use of dynamic content for all aspects and is easily configurable / overridable.
Here's what you'll learn...
How to install & configure the plugin
How to use default dialog service
How to enhance & replace parts of the default implementations
The lifeycle of a dialog
Installing The Plugin
There's a set of default implementations for the main interfaces of the Dialog plugin, which includes:
IDialogService
IDialogGlobalSettings
IDialogDomRenderer
These default implementation are grouped in the export named DialogDefaultConfiguration of the dialog plugin, which can be used per the following:
import { DialogDefaultConfiguration } from '@aurelia/dialog';
import { Aurelia } from 'aurelia';
​
Aurelia.register(DialogDefaultConfiguration).app(MyApp).start();
Configuring the Plugin
The export DialogDefaultConfiguration is a preset of default behaviors & implementations that are done in a way suitable to most common scenarios.
If it's desirable to change some of the behaviors or implementations of we can either change the first or the 2nd parameter of the customize function on this object.
An example of changing the behavior for configuring the global settings is:
Aurelia.register(DialogDefaultConfiguration.customize(globalSettings => {
  // change global settings ...
})).app(MyApp).start()
If it's desirable to change some of the default implementations, we can instead use the export named DialogConfiguration and pass in the list of implementation for the main interfaces:
import { DialogConfiguration } from '@aurelia/dialog';
​
Aurelia.register(DialogConfiguration.customize(settings => {
​
}, [
  // all custom implementation
  MyDialogService,
  MyDialogRenderer,
  MyDialogGlobalSettings,
]))
If there's a need to only swap some implementation, say IDialogDomRenderer for example, then the default implementation can be imported and mixed like the following example:
import { DialogConfiguration, DialogService, DefaultDialogGlobalSettings } from '@aurelia/dialog';
​
Aurelia.register(DialogConfiguration.customize(settings => {
​
}, [
  // use default dialog service
  DialogService,
  // BYO dialog dom renderer
  MyDialogRenderer,
  // use default dialog global settings
  DefaultDialogGlobalSettings,
]))
Using The Default Implementation
The Dialog Settings
There are two levels where dialog behavior can be configured:
Global level via IDialogGlobalSettings
Single dialog level via property settings on a dialog controller.
Normally, the global settings would be changed during the app startup/or before, while the single dialog settings would be changed during the contruction of the dialog view model, via the open method.
An example of configuring the global dialog settings:
Make all dialogs, by default:
not dismissable by clicking outside of it, or hitting the ESC key
have starting CSS z-index of 5
if not locked, closable by hitting the ESC key
Aurelia.register(DialogDefaultConfiguration.customize(settings => {
settings.lock = true;
settings.startingZIndex = 5;
settings.keyboard = true;
})).app(MyApp).start()
An example of configuring a single dialog, via open method of the dialog service:
Displaying an alert dialog, which has z-index value as 10 to stay on top of all other dialogs, and will be dismissed when the user hits the ESC key.
dialogService.open({
  component: () => Alert,
  lock: false,
  startingZIndex = 10,
})
The settings that are available in the open method of the dialog service:
component can be class reference or instance, or a function that resolves to such, or a promise of such.
template can be HTML elements, string or a function that resolves to such, or a promise of such.
model the data to be passed to the canActivate and activate methods of the view model if implemented.
host allows providing the element which will parent the dialog - if not provided the document body will be used.
container allows specifying the DI Container instance to be used for the dialog. If not provided a new child container will be created from the root one.
lock makes the dialog not dismissable via clicking outside, or using keyboard.
keyboard allows configuring keyboard keys that close the dialog. To disable set to an empty array []. To cancel close a dialog when the ESC key is pressed set to an array containing 'Escape' - ['Escape']. To close with confirmation when the ENTER key is pressed set to an array containing 'Enter' - ['Enter']. To combine the ESC and ENTER keys set to ['Enter', 'Escape'] - the order is irrelevant. (takes precedence over lock)
overlayDismiss if set to true cancel closes the dialog when clicked outside of it. (takes precedence over lock)
rejectOnCancel is a boolean that must be set to true if cancellations should be treated as rejection. The reason will be an IDialogCancelError - the property wasCancelled will be set to true and if cancellation data was provided it will be set to the value property.
The default global settings has the following values:
lock is true
startingZIndex is 1000
rejectOnCancel is false
If rejectOnCancel behavior is desired, it should only be applied to individual dialog via open method of the dialog service.
The Dialog Service APIs
The interface that a dialog service should follow:
interface IDialogService {
  readonly controllers: IDialogController[];
​
  /**
   * Opens a new dialog.
   *
   * @param settings - Dialog settings for this dialog instance.
   * @returns Promise A promise that settles when the dialog is closed.
   */
  open(settings?: IDialogSettings): DialogOpenPromise;
​
  /**
   * Closes all open dialogs at the time of invocation.
   *
   * @returns Promise<DialogController[]> All controllers whose close operation was cancelled.
   */
  closeAll(): Promise<IDialogController[]>;
}
The interface that a dialog controller should follow:
interface IDialogController {
  readonly settings: Readonly<ILoadedDialogSettings>;
  /**
   * A promise that will be fulfilled once this dialog has been closed
   */
  readonly closed: Promise<DialogCloseResult>;
​
  ok(value?: unknown): Promise<DialogCloseResult<DialogDeactivationStatuses.Ok>>;
  cancel(value?: unknown): Promise<DialogCloseResult<DialogDeactivationStatuses.Cancel>>;
  error(value?: unknown): Promise<void>;
}
An important feature of the dialog plugin is that it is possible to resolve and close (using cancel/ok/error methods) a dialog in the same context where it's open.
Example of controlling the opening and closing of a dialog in promise style:
import { EditPerson } from './edit-person';
import { IDialogService, DialogDeactivationStatuses } from '@aurelia/dialog';
​
export class Welcome {
  static inject = [IDialogService];
​
  person = { firstName: 'Wade', middleName: 'Owen', lastName: 'Watts' };
  constructor(dialogService) {
    this.dialogService = dialogService;
  }
​
  submit() {
    this.dialogService
      .open({ component: () => EditPerson, model: this.person })
      .then(openDialogResult => {
        // Note:
        // We get here when the dialog is opened,
        // and we are able to close dialog
        setTimeout(() => {
          openDialogResult.dialog.cancel('Failed to finish editing after 3 seconds');
        }, 3000);
​
        // each dialog controller should expose a promise for attaching callbacks
        // to be executed for when it has been closed
        return openDialogResult.dialog.closed;
      })
      .then((response) => {
        if (response.status === DialogDeactivationStatuses.Ok) {
          console.log('good');
        } else {
          console.log('bad');
        }
        console.log(response);
      });
  }
}
Example of controlling the opening and closing of a dialog using async/await:
import { EditPerson } from './edit-person';
import { IDialogService, DialogDeactivationStatuses } from '@aurelia/dialog';
​
export class Welcome {
  static inject = [IDialogService];
​
  person = { firstName: 'Wade', middleName: 'Owen', lastName: 'Watts' };
  constructor(dialogService) {
    this.dialogService = dialogService;
  }
​
  async submit() {
    const { dialog } = await this.dialogService.open({
      component: () => EditPerson,
      model: this.person
    });
    // Note:
    // We get here when the dialog is opened,
    // and we are able to close dialog
    setTimeout(() => {
      dialog.cancel('Failed to finish editing after 3 seconds');
    }, 3000);
​
    const response = await dialog.closed;
    if (response.status === DialogDeactivationStatuses.Ok) {
      console.log('good');
    } else {
      console.log('bad');
    }
    console.log(response);
  }
}
By default, when an application is destroyed, the dialog service of that application will also try to close all the open dialogs that are registered with it via closeAll method. It can also be used whenever there's a need to forcefully close all open dialogs, as per following example:
Given an error list, open a dialog for each error, and close all of them after 5 seconds.
import { Alert } from './dialog-alert';
import { IDialogService, DialogDeactivationStatuses } from '@aurelia/dialog';
​
export class Welcome {
  static inject = [IDialogService];
​
  constructor(dialogService) {
    this.dialogService = dialogService;
  }
​
  notifyErrors(errors) {
    // for each of the error in the given error
    errors.forEach(error => {
      this.dialogService.open({ component: () => Alert, model: error });
    });
​
    setTimeout(() => this.dialogService.closeAll(), 5000);
  }
}
If there's no need for the opening result of a dialog, and only the response of it after the dialog has been closed, there is a whenClosed method exposed on the returned promise of the open method of the dialog service, that should help reduce some boilerplate code, per following example:
import { EditPerson } from './edit-person';
import { IDialogService, DialogDeactivationStatuses } from '@aurelia/dialog';
​
export class Welcome {
  static inject = [IDialogService];
​
  person = { firstName: 'Wade', middleName: 'Owen', lastName: 'Watts' };
  constructor(dialogService) {
    this.dialogService = dialogService;
  }
​
  submit() {
    this.dialogService
      .open({ component: () => EditPerson, model: this.person })
      .whenClosed(response => {
        console.log('The edit dialog has been closed');
        if (response.status === DialogDeactivationStatuses.Ok) {
          console.log('good');
        } else {
          console.log('bad');
        }
        console.log(response);
      })
      .catch(err => {
        console.log('Failed to edit person information');
      });
  }
}
Template Only Dialogs
The dialog service supports rendering dialogs with only template specified. A template only dialog can be open like the following examples:
dialogService.open({
  template: () => fetch('https://some-server.com/alert-dialog.html').then(r => r.text()),
  template: () => '<div>Welcome to Aurelia</div>',
  template: '<div>Are you ready?</div>'
})
Retrieving the dialog controller
By default, the dialog controller of a dialog will be assigned automatically to the property $dialog on the component view model. To specify this in TypeScript, the component class can implement the interface IDialogCustomElementViewModel:
import { IDialogController, IDialogCustomElementViewModel } from '@aurelia/dialog';
​
class MyDialog implements IDialogCustomElementViewModel {
  $dialog: IDialogController;
​
  closeDialog() {
    this.$dialog.ok('All good!');
  }
}
Note that the property $dialog will only be ready after the contructor.
If it's desirable to retrieve the associated dialog controller of a dialog during the constructor of the component, IDialogController can be inject to achieve the same effect:
import { IDialogController } from '@aurelia/dialog';
​
@inject(IDialogController)
class MyDialog {
  constructor(dialog) {
    // change some settings
    dialog.settings.zIndex = 100;
  }
}
This means it's also possible to control the dialog from template only dialog via the $dialog property. An example of this is: Open an alert dialog, and display an "Ok" button to close it, without using any component:
dialogService.open({
  template: `<div>
    Please check the oven!
    <button click.trigger="$dialog.ok()">Close and check</button>
  </div>`
})
The Default Dialog Renderer
By default, the dialog DOM structure is rendered as follow:
> (1) Dialog host element
  > (2) Dialog Wrapper Element
    > (3) Dialog Overlay Element
    > (4) Dialog Content Host Element
The Dialog host element is the target where an application chooses to add the dialog to, this is normally the document body, if not supplied in the settings of the open method of the dialog service.
An example of the html structure when document body is the dialog host:
<body>
  <au-dialog-container> <!-- wrapper -->
    <au-dialog-overlay> <!-- overlay -->
    <div> <!-- dialog content host -->
Centering/Uncentering dialog position
By default, the dialog content host is centered horizontally and vertically. It can be changed via IDialogDom injection:
import { IDialogDom, DefaultDialogDom } from '@aurelia/dialog';
​
@inject(IDialogDom)
export class MyDialog {
  constructor(dialogDom: DefaultDialogDom) {
    dialogDom.contentHost.style.margin = "0 auto"; // only center horizontally
  }
}
Note that the contentHost property on a DefaultDialogDom object is the same with the host element of a component. You can inject IDialogDom and retrieve the host element via contentHost property, or inject INode/Element/HTMLElement to retrieve it.
Styling the overlay
By default, the overlay of a dialog is transparent. Though it's often desirable to add 50% opacity and a background color of black to the modal. To achieve this in dialog, retrieve the IDialogDom instance and modify the overlay element style:
import { IDialogDom, DefaultDialogDom } from '@aurelia/dialog';
​
@inject(IDialogDom)
export class MyDialog {
  constructor(dialogDom: DefaultDialogDom) {
    dialogDom.overlay.style.backgroundColor = "rgba(0, 0, 0, 0.5)";
  }
}
BYO Dialog Renderer
... todo
Animation
The lifecycles attaching and detaching can be used to animate a dialog, as in those lifecycles, if a promise is returned, it will be awaited during the activation/deactivation phases.
An example of animating a dialog on attaching and detaching, with the animation duration of 200 milliseconds:
@inject(Element)
export class MyDialog {
  constructor(host: Element) {
    this.host = host;
  }
​
  attaching() {
    const animation = this.host.animate(
      [{ transform: 'translateY(0px)' }, { transform: 'translateY(-300px)' }],
      { duration: 200 },
    );
    return animation.finished;
  }
​
  detaching() {
    const animation = this.host.animate(
      [{ transform: 'translateY(-300px)' }, { transform: 'translateY(0)' }],
      { duration: 200 },
    );
    return animation.finished;
  }
}
Component Lifecycles With The Dialog Plugin
In adition to the lifecycle hooks defined in the core templating, the dialog defines additional ones. All dialog specific hooks can return a Promise, that resolves to the appropriate value for the hook, and will be awaited.
.canActivate()
This hook can be used to cancel the opening of a dialog. It is invoked with one parameter - the value of the model setting passed to .open(). To cancel the opening of the dialog return false - null and undefined will be coerced to true.
.activate()
This hook can be used to do any necessary init work. The hook is invoked with one parameter - the value of the model setting passed to .open().
.canDeactivate(result: DialogCloseResult)
This hook can be used to cancel the closing of a dialog. To do so return false - null and undefined will be coerced to true. The passed in result parameter has a property status, indicating if the dialog was closed or cancelled, or the deactivation process itself has been aborted, and an value property with the dialog result which can be manipulated before dialog deactivation.
The DialogCloseResult has the following interface (simplified):
interface DialogCloseResult {
  readonly status: 'Ok' | 'Cancel' | 'Abort' | 'Error';
  readonly value?: unknown;
}
Warning When the error method of a DialogController is called this hook will be skipped.
.deactivate(result: DialogCloseResult)
This hook can be used to do any clean up work. The hook is invoked with one result parameter that has a property status, indicating if the dialog was closed (Ok) or cancelled (Cancel), and an value property with the dialog result.
Order of Invocation
Each dialog instance goes through the full lifecycle once.
--- activation phase:
1.constructor()
2..canActivate() - dialog specific
3..activate() - dialog specific
4.define
5.hydrating
6.hydrated
7..created()
8..binding()
9..bound()
10.attaching
11.attached
--- deactivation phase:
1..canDeactivate() - dialog specific
2..deactivate() - dialog specific
3..detaching()
4..unbinding()
V1 Dialog Migration
viewModel setting in DialogService.prototype.open is changed to component.
view setting in DialogService.prototype.open is changed to template.
keyboard setting in DialogService.prototype.open is changed to accept an array of Enter/Escape only. Boolean variants are no longer valid. In the future, the API may become less strict.
The resolved of DialogService.prototype.open is changed from:
  interface DialogOpenResult {
    wasCancelled: boolean;
    controller: DialogController;
    closeResult: Promise<DialogCloseResult>;
  }
to:
  interface DialogOpenResult {
    wasCancelled: boolean;
    dialog: IDialogController;
  }
closeResult is removed from the returned object. Uses closed property on the dialog controller instead, example of open a dialog with hello world text, and automaticlly close after 2 seconds:
  dialogService
    .open({ template: 'hello world' })
    .then(({ dialog }) => {
      setTimeout(() => { dialog.ok() }, 2000)
      return dialog.closed
    });
The interface of dialog close results is changed from:
  interface DialogCloseResult {
    wasCancelled: boolean;
    output?: unknown;
  }
to:
  interface DialogCloseResult {
    status: DialogDeactivationStatus;
    value?: unknown;
  }
The dialog controller is assigned to property $dialog (v2) on the view model, instead of property controller (v1)
TODO: links to advanced examples/playground

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Dialog

Introduction

Installing The Plugin

Configuring the Plugin

Using The Default Implementation

The Dialog Settings

The Dialog Service APIs

The Default Dialog Renderer

Centering/Uncentering dialog position

Styling the overlay

BYO Dialog Renderer

Animation

Component Lifecycles With The Dialog Plugin

`.canActivate()`

`.activate()`

`.canDeactivate(result: DialogCloseResult)`

`.deactivate(result: DialogCloseResult)`

Order of Invocation

V1 Dialog Migration