Class RouterService

Adds an observer on a property.

This is the core method used to register an observer for a property.

Once you call this method, any time the key's value is set, your observer will be notified. Note that the observers are triggered any time the value is set, regardless of whether it has actually changed. Your observer should be prepared to handle that.

There are two common invocation patterns for .addObserver():

• Passing two arguments:
• the name of the property to observe (as a string)
• the function to invoke (an actual function)
• Passing three arguments:
• the name of the property to observe (as a string)
• the target object (will be used to look up and invoke a function on)
• the name of the function to invoke on the target object (as a string).

import Component from '@ember/component';

export default Component.extend({
  init() {
    this._super(...arguments);

    // the following are equivalent:

    // using three arguments
    this.addObserver('foo', this, 'fooDidChange');

    // using two arguments
    this.addObserver('foo', (...args) => {
      this.fooDidChange(...args);
    });
  },

  fooDidChange() {
    // your custom logic code
  }
});

Observer Methods

Observer methods have the following signature:

import Component from '@ember/component';

export default Component.extend({
  init() {
    this._super(...arguments);
    this.addObserver('foo', this, 'fooDidChange');
  },

  fooDidChange(sender, key, value, rev) {
    // your code
  }
});

The sender is the object that changed. The key is the property that changes. The value property is currently reserved and unused. The rev is the last property revision of the object when it changed, which you can use to detect if the key value has really changed or not.

Usually you will not need the value or revision parameters at the end. In this case, it is common to write observer methods that take only a sender and key value as parameters or, if you aren't interested in any of these values, to write an observer that has no parameters at all.

Returns the cached value of a computed property, if it exists. This allows you to inspect the value of a computed property without accidentally invoking it if it is intended to be generated lazily.

Set the value of a property to the current value minus some amount.

player.decrementProperty('lives');
orc.decrementProperty('health', 5);

Destroys an object by setting the isDestroyed flag and removing its metadata, which effectively destroys observers and bindings.

If you try to set a property on a destroyed object, an exception will be raised.

Note that destruction is scheduled for the end of the run loop and does not happen immediately. It will set an isDestroying flag immediately.

Retrieves the value of a property from the object.

This method is usually similar to using object[keyName] or object.keyName, however it supports both computed properties and the unknownProperty handler.

Because get unifies the syntax for accessing all these kinds of properties, it can make many refactorings easier, such as replacing a simple property with a computed property, or vice versa.

Computed Properties

Computed properties are methods defined with the property modifier declared at the end, such as:

import { computed } from '@ember/object';

fullName: computed('firstName', 'lastName', function() {
  return this.get('firstName') + ' ' + this.get('lastName');
})

When you call get on a computed property, the function will be called and the return value will be returned instead of the function itself.

Unknown Properties

Likewise, if you try to call get on a property whose value is undefined, the unknownProperty() method will be called on the object. If this method returns any value other than undefined, it will be returned instead. This allows you to implement "virtual" properties that are not defined upfront.

To get the values of multiple properties at once, call getProperties with a list of strings or an array:

record.getProperties('firstName', 'lastName', 'zipCode');
// { firstName: 'John', lastName: 'Doe', zipCode: '10011' }

is equivalent to:

record.getProperties(['firstName', 'lastName', 'zipCode']);
// { firstName: 'John', lastName: 'Doe', zipCode: '10011' }

Set the value of a property to the current value plus some amount.

person.incrementProperty('age');
team.incrementProperty('score', 2);

An overridable method called when objects are instantiated. By default, does nothing unless it is overridden during class definition.

Example:

import EmberObject from '@ember/object';

const Person = EmberObject.extend({
  init() {
    alert(`Name is ${this.get('name')}`);
  }
});

let steve = Person.create({
  name: 'Steve'
});

// alerts 'Name is Steve'.

NOTE: If you do override init for a framework class like Component from @ember/component, be sure to call this._super(...arguments) in your init declaration! If you don't, Ember may not have an opportunity to do important setup work, and you'll see strange behavior in your application.

Returns true if routeName/models/queryParams is the active route, where models and queryParams are optional. See model and queryParams for more information about these arguments.

In the following example, isActive will return true if the current route is /posts.

import Component from '@glimmer/component';
import { service } from '@ember/service';

export default class extends Component {
  @service router;

  displayComments() {
    return this.router.isActive('posts');
  }
});

The next example includes a dynamic segment, and will return true if the current route is /posts/1, assuming the post has an id of 1:

import Component from '@glimmer/component';
import { service } from '@ember/service';

export default class extends Component {
  @service router;

  displayComments(post) {
    return this.router.isActive('posts', post.id);
  }
});

Where post.id is the id of a specific post, which is represented in the route as /posts/[post.id]. If post.id is equal to 1, then isActive will return true if the current route is /posts/1, and false if the route is anything else.

Notify the observer system that a property has just changed.

Sometimes you need to change a value directly or indirectly without actually calling get() or set() on it. In this case, you can use this method instead. Calling this method will notify all observers that the property has potentially changed value.

You can unregister a listener for events emitted by this service with .off():

import Route from '@ember/routing';
import { service } from '@ember/service';

export default class extends Route {
  @service router;

  callback = (transition) =>  {
    if (!transition.to.find(route => route.name === this.routeName)) {
      alert("Please save or cancel your changes.");
      transition.abort();
    }
  };

  activate() {
    this.router.on('routeWillChange', this.callback);
  }

  deactivate() {
    this.router.off('routeWillChange', this.callback);
}

You can register a listener for events emitted by this service with .on():

import Route from '@ember/routing';
import { service } from '@ember/service';

export default class extends Route {
  @service router;

  activate() {
    this.router.on('routeWillChange', (transition) => {
      if (!transition.to.find(route => route.name === this.routeName)) {
        alert("Please save or cancel your changes.");
        transition.abort();
      }
    })
  }
}

Takes a string URL and returns a RouteInfo for the leafmost route represented by the URL. Returns null if the URL is not recognized. This method expects to receive the actual URL as seen by the browser including the app's rootURL.

See RouteInfo for more info.

In the following example recognize is used to verify if a path belongs to our application before transitioning to it.

import Component from '@ember/component';
import { service } from '@ember/service';

export default class extends Component {
  @service router;
  path = '/';

  click() {
    if (this.router.recognize(this.path)) {
      this.router.transitionTo(this.path);
    }
  }
}

Takes a string URL and returns a promise that resolves to a RouteInfoWithAttributes for the leafmost route represented by the URL. The promise rejects if the URL is not recognized or an unhandled exception is encountered. This method expects to receive the actual URL as seen by the browser including the app's rootURL.

Refreshes all currently active routes, doing a full transition. If a route name is provided and refers to a currently active route, it will refresh only that route and its descendents. Returns a promise that will be resolved once the refresh is complete. All resetController, beforeModel, model, afterModel, redirect, and setupController hooks will be called again. You will get new data from the model hook.

Remove an observer you have previously registered on this object. Pass the same key, target, and method you passed to addObserver() and your target will no longer receive notifications.

Similar to transitionTo, but instead of adding the destination to the browser's URL history, it replaces the entry for the current route. When the user clicks the "back" button in the browser, there will be fewer steps. This is most commonly used to manage redirects in a way that does not cause confusing additions to the user's browsing history.

Calling replaceWith from the Router service will cause default query parameter values to be included in the URL. This behavior is different from calling replaceWith on a route. See the Router Service RFC for more info.

Usage example:

import Route from '@ember/routing/route';

export default class extends Route {
  beforeModel() {
    if (!authorized()){
      this.replaceWith('unauthorized');
    }
  }
});

Sets the provided key or path to the value.

record.set("key", value);

This method is generally very similar to calling object["key"] = value or object.key = value, except that it provides support for computed properties, the setUnknownProperty() method and property observers.

Computed Properties

If you try to set a value on a key that has a computed property handler defined (see the get() method for an example), then set() will call that method, passing both the value and key instead of simply changing the value itself. This is useful for those times when you need to implement a property that is composed of one or more member properties.

Unknown Properties

If you try to set a value on a key that is undefined in the target object, then the setUnknownProperty() handler will be called instead. This gives you an opportunity to implement complex "virtual" properties that are not predefined on the object. If setUnknownProperty() returns undefined, then set() will simply set the value on the object.

Property Observers

In addition to changing the property, set() will also register a property change with the object. Unless you have placed this call inside of a beginPropertyChanges() and endPropertyChanges(), any "local" observers (i.e. observer methods declared on the same object), will be called immediately. Any "remote" observers (i.e. observer methods declared on another object) will be placed in a queue and called at a later time in a coalesced manner.

Sets a list of properties at once. These properties are set inside a single beginPropertyChanges and endPropertyChanges batch, so observers will be buffered.

record.setProperties({ firstName: 'Charles', lastName: 'Jolley' });

Returns a string representation which attempts to provide more information than Javascript's toString typically does, in a generic way for all Ember objects.

import EmberObject from '@ember/object';

const Person = EmberObject.extend();
person = Person.create();
person.toString(); //=> "<Person:ember1024>"

If the object's class is not defined on an Ember namespace, it will indicate it is a subclass of the registered superclass:

const Student = Person.extend();
let student = Student.create();
student.toString(); //=> "<(subclass of Person):ember1025>"

If the method toStringExtension is defined, its return value will be included in the output.

const Teacher = Person.extend({
  toStringExtension() {
    return this.get('fullName');
  }
});
teacher = Teacher.create();
teacher.toString(); //=> "<Teacher:ember1026:Tom Dale>"

Set the value of a boolean property to the opposite of its current value.

starship.toggleProperty('warpDriveEngaged');

Transition the application into another route. The route may be either a single route or route path:

Calling transitionTo from the Router service will cause default query parameter values to be included in the URL. This behavior is different from calling transitionTo on a route or transitionToRoute on a controller. See the Router Service RFC for more info.

In the following example we use the Router service to navigate to a route with a specific model from a Component in the first action, and in the second we trigger a query-params only transition.

import Component from '@glimmer/component';
import { action } from '@ember/object';
import { service } from '@ember/service';

export default class extends Component {
  @service router;

  @action
  goToComments(post) {
    this.router.transitionTo('comments', post);
  }

  @action
  fetchMoreComments(latestComment) {
    this.router.transitionTo({
      queryParams: { commentsAfter: latestComment }
    });
  }
}

Generate a URL based on the supplied route name and optionally a model. The URL is returned as a string that can be used for any purpose.

In this example, the URL for the author.books route for a given author is copied to the clipboard.

<CopyLink @author={{hash id="tomster" name="Tomster"}} />

import Component from '@glimmer/component';
import { service } from '@ember/service';
import { action } from '@ember/object';

export default class CopyLinkComponent extends Component {
  @service router;
  @service clipboard;

  @action
  copyBooksURL() {
    if (this.author) {
      const url = this.router.urlFor('author.books', this.args.author);
      this.clipboard.set(url);
      // Clipboard now has /author/tomster/books
    }
  }
}

Just like with transitionTo and replaceWith, urlFor can also handle query parameters.

<CopyLink @author={{hash id="tomster" name="Tomster"}} />

import Component from '@glimmer/component';
import { service } from '@ember/service';
import { action } from '@ember/object';

export default class CopyLinkComponent extends Component {
  @service router;
  @service clipboard;

  @action
  copyOnlyEmberBooksURL() {
    if (this.author) {
      const url = this.router.urlFor('author.books', this.author, {
        queryParams: { filter: 'emberjs' }
      });
      this.clipboard.set(url);
      // Clipboard now has /author/tomster/books?filter=emberjs
    }
  }
}

Override to implement teardown.