Front End Developer Interview Questions

Q1: What do you think are the fundamental skills Front end developer must have?

Ans: A good front-end developer should be proficient in the following languages:

  • HTML
  • JQuery
  • CSS
  • JavaScript

The abilities listed above are some of the fundamentals of becoming a front-end developer. Aside from the technical abilities required of a front-end developer.

  • Knowledge of Content Management Systems such as Drupal, Joomla, and WordPress.
  • Understanding of PHP and OOP.
  • Understanding of cross-browser testing.
  • Understanding of SEO and technologies like Flash and Dreamweaver that are utilized to convey web-based knowledge to end consumers.

Q2: How to optimize the page through front-end technology or code?

Ans: The following are some of the finest front-end technological practices for optimizing a web page.

  • Increase overall server response time by reducing per-page resource use.
    • Combine all JavaScript external documents into a single document.
  • Avoid using block-level JavaScript in favor of asynchronous JavaScript.
  • Optimize the image and use the proper image format. For big pictures, use the slow loading design approach.
  • Plugins should not be used to improve overall functioning.
  • Emphasize visible material.
    • Combine several CSS files into a single file.
  • Use responsive design rather than device-specific redirection.
  • Make use of the Minify JavaScript and CSS versions.
  • Make use of CSS best practices and organize the viewport
  • Include scripts in the footer and style sheets in the header.

Q3: What is JavaScript Scope?

Ans: Every function in JavaScript has its scope. The scope is defined as a set of variables as well as the principles for accessing the variables by name. Only the function's code has access to the function's scoped variables.

Each variable name should be unique within the same scope. We may even stack one scope within another. In this scenario, the innermost scope's function has access to variables from another scope.

Q4: What is Sass?

Ans: Sass, or Syntactically Awesome Stylesheets, is a CSS preprocessor that adds beauty and power to the fundamental language. It supports nested rules, variables, inline imports, mixins, and other features. CSS should be supported by syntax. Sass assists in organizing big stylesheets and keeping small stylesheets operational.

The CSS preprocessor is also a scripting language that broadens CSS by allowing developers to create code in one language and then aggregate it in CSS. What is the distinction between "normalizing" and "resetting" CSS? Which one would you pick?

  • Normalizing — saves crucial default styles before "unstyling" everything. It resolves problems and issues for common browser requirements.
  • Resetting — is designed to remove the default browser's style from elements. For example, paddings, margins, and font sizes of components are being rearranged to be the same. You must redeclare the style for common typographic components.

When you have a highly unique or customized website design that I want to make my own creating, there is no need for any default styling to be well-maintained.

Q5: What is meant by SOLID? Explain its principles?

Ans: S.O.L.I.D. stands for Robert C. Martin's first five object-oriented design principles.

  • S — Principle of single-responsibility. To alter, a class must have only one purpose, which means that each class should have only one duty.
  • O — Principle of open-closed. Entities or Objects must be open to extension but closed to modification.
  • The substitution concept of L – Liskov. Allow q(x) to be verifiable about x objects of type T. Then q(y) must be verifiable for y objects of type S, where S is a subclass of T.
  • I – The principle of interface isolation. A customer must never be compelled to use an interface that it does not use, and customers must never be made to rely on methods that they do not utilize.
  • D - Principle of Dependency Inversion. Entities should be founded on abstractions, not concretions. It specifies that the high-level unit should not be based on the low-level module, but rather on abstractions.