Ember.js supports a wide range of events that developers can utilize to build interactive web applications. These events include:
- Click: This event occurs when a user clicks on an element.
- Double click: It is triggered when a user quickly clicks twice on an element.
- Mouse enter: This event is fired when the mouse pointer enters the boundaries of an element.
- Mouse leave: It is triggered when the mouse pointer exits the boundaries of an element.
- Key press: This event occurs when a key on the keyboard is pressed and released.
- Key down: It is triggered when a key on the keyboard is pressed.
- Key up: It is fired when a key on the keyboard is released.
- Touch start: This event is fired when a touch point is placed on the touch surface.
- Touch end: It occurs when a touch point is removed from the touch surface.
- Focus in: This event is triggered when an element receives focus.
- Focus out: It is fired when an element loses focus.
- Submit: This event occurs when a form is submitted.
- Scroll: It is triggered when the user scrolls the content of an element.
- Drag start: This event is fired when an element starts being dragged.
- Drag end: It occurs when an element finishes being dragged.
- Resize: This event is triggered when the size of an element is changed.
- Error: It is fired when an error occurs during the loading of an external resource, such as an image or script.
These events, along with many others, enable developers to create rich and interactive user experiences using Ember.js.
Best Ember.js Books to Read in 2024
What is the purpose of events in Ember.js?
The purpose of events in Ember.js is to handle user interactions and trigger specific actions within the application. They enable developers to respond to different user actions, such as clicks, keypresses, etc., and update the application's state or perform other desired actions accordingly. Events in Ember.js are typically handled using event handlers, which are defined in the application's components or controllers.
What is the Ember Evented mixin for handling events?
The Ember Evented mixin is a utility provided by the Ember.js framework for implementing event handling functionality in Ember objects. It allows objects to bind and trigger events, similar to the concept of event listeners and dispatchers in other programming languages and frameworks.
To use the Evented mixin in an Ember object, perform the following steps:
- Import 'Evented' from the '@ember/object' module: import { Evented } from '@ember/object';
- Extend your object from the Evented mixin: export default EmberObject.extend(Evented, { // Object properties and methods... });
- Bind events using the 'on' method: this.on('eventname', this, 'methodName');
- Trigger events using the 'trigger' method: this.trigger('eventname', eventData);
- Handle events in the appropriate method: methodName(eventData) { // Event handling logic... }
The Evented mixin provides a way to define custom events and propagate events throughout the Ember object hierarchy. It is commonly used to facilitate communication between components and other objects in an Ember application.
What is the difference between bubbling and capturing events in Ember.js?
Bubbling and capturing events in Ember.js refer to the way in which events are propagated through the DOM tree.
Bubbling is the default behavior in Ember.js events. When an event is triggered on an element, it first gets handled by that element, then it "bubbles" up the DOM tree, triggering the same event on its parent elements. For example, if you have a button inside a div, and a click event is triggered on the button, the button's click event handler will be invoked first, followed by the div's event handler (if any).
Capturing, on the other hand, is the opposite of bubbling. In capturing, the event starts at the highest level (usually the root element) and propagates downwards through the DOM tree. So the event would first trigger on the div in the above example, and then on the button.
In Ember.js, bubbling and capturing can be controlled using the following event modifiers:
- bubbles: This modifier specifies whether the event should bubble up the DOM tree. By default, it is set to true, enabling bubbling. You can set it to false to prevent the event from bubbling.
- capture: This modifier specifies whether the event should be captured during the capture phase. By default, it is set to false, disabling capturing. You can set it to true to enable event capturing.
For example, to disable bubbling and enable capturing for a specific event in Ember.js, you can use the following code:
1 2 3 4 5 6 |
<div {{did-insert this.handleEvent}}>Button</div> handleEvent(e) { e.stopPropagation(); // Prevent event from bubbling up console.log("Captured event"); } |
In this example, the did-insert modifier is used to attach the event handler to the div element. The e.stopPropagation() call prevents the event from bubbling up the DOM tree, and the console will log "Captured event" when the event is triggered.
What are the commonly used built-in events in Ember.js?
Some commonly used built-in events in Ember.js are:
- init: Triggered when the object is initialized.
- didInsertElement: Triggered when the component is inserted into the DOM.
- willDestroyElement: Triggered when the component is about to be removed from the DOM.
- didRender: Triggered after the component is rendered.
- click: Triggered when a click event occurs on an element.
- keyUp: Triggered when a keyup event occurs on an element.
- submit: Triggered when a form is submitted.
- willTransition: Triggered when the route is about to transition to another route.
- didTransition: Triggered after the route has transitioned to another route.
- error: Triggered when an error occurs during a promise or route transition.
These are just a few examples, and Ember.js provides many more built-in events that can be used for various purposes.
