Top questions with answers asked in MNC on Ember.js

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Ember.js interview questions along with their answers that might be asked in top multinational companies (MNCs):

  1. What is Ember.js, and what are its key features?
    • Answer: Ember.js is an open-source JavaScript framework for building scalable single-page web applications. It follows the Model-View-ViewModel (MVVM) architecture pattern and provides a set of conventions for structuring code and managing application state. Key features of Ember.js include:
      • Two-way data binding: Changes to the model automatically update the view, and changes to the view update the model.
      • Routing: Ember.js provides a powerful routing system for managing application navigation and state.
      • Templating: Ember.js uses Handlebars.js templating engine to create dynamic HTML content based on application data.
      • Ember Data: Ember.js includes Ember Data, a library for managing model data and communicating with a server-side API using RESTful conventions.
      • CLI (Command Line Interface): Ember CLI is a powerful tool for generating and managing Ember.js projects, including scaffolding, testing, and deployment.
  2. Explain the concept of “Components” in Ember.js and how they differ from “Controllers” and “Views”.
    • Answer: In Ember.js, components are reusable UI elements that encapsulate both markup and behavior. They are similar to custom HTML elements and can be used to create complex user interfaces. Components have their own template, JavaScript class (component class), and optional CSS styles. Unlike controllers and views, which are primarily concerned with managing application state and rendering templates, components focus on encapsulating reusable UI logic and promoting code reusability. Components have their own isolated scope, making them self-contained and independent of the surrounding application context.
  3. What is Ember Data, and how does it facilitate data management in Ember.js applications?
    • Answer: Ember Data is a library included in Ember.js for managing model data and communicating with a server-side API using RESTful conventions. It provides a uniform interface for defining models, querying data, and performing CRUD (Create, Read, Update, Delete) operations. Ember Data follows the Active Record pattern, where each model class represents a type of resource (e.g., user, post, comment) and encapsulates data-related logic and behavior. Ember Data abstracts away the complexities of data loading and synchronization by providing features like adapters and serializers, which handle communication with the backend server and data transformation.
  4. Explain Ember.js routing and how it enables the creation of single-page applications (SPAs).
    • Answer: Ember.js routing is a powerful feature that enables the creation of single-page applications (SPAs) by managing application state and navigation without page reloads. Ember.js uses a hierarchical routing system where each route corresponds to a specific URL and application state. Routes define model data, template rendering, and actions associated with a particular URL. Ember.js provides a router DSL (Domain-Specific Language) for defining routes, nested routes, and route hooks such as beforeModel, model, afterModel, etc. Routing in Ember.js facilitates the creation of SPAs with smooth transitions between application states, bookmarkable URLs, and deep linking.
  5. What are the best practices for testing Ember.js applications, and what tools does Ember.js provide for testing?
    • Answer: Testing is an essential part of Ember.js development to ensure code quality, reliability, and maintainability. Best practices for testing Ember.js applications include:
      • Unit testing: Test individual components, controllers, routes, and helpers in isolation using tools like QUnit or Mocha.
      • Integration testing: Test the interaction between multiple components, controllers, and templates using tools like Ember’s built-in test helpers and the Ember Testing API.
      • Acceptance testing: Test application features and user interactions from end to end using tools like Ember CLI Mirage for mocking backend data and Ember’s acceptance test helpers.
      • Continuous Integration (CI): Set up automated testing pipelines using CI services like Travis CI or CircleCI to run tests on every code commit and ensure code stability across different environments.