5 JavaScript Concepts to Brush Up On Before Your Next IT Interview

Programmers hate to interview. Many times recruiters don’t really understand how to code, and there is always the dreaded coding test that many companies use in their prescreening process. If you’ve been programming for years, going back to fundamental concepts you may use every day but have forgotten the theories behind will be beneficial for your next interview.  

JavaScript is one of the languages of choice for many developers today. Preparing for the questions you’ll face in the job interview can be tricky whether you’ve been developing for 10 months or 10 years. Ultimately, it’s important to keep in mind that JavaScript is a tool designed to solve a problem—and that problem can be solved in different ways. 

Here are five JavaScript concepts should you know for your next interview. 

JavaScript Interview Tips 

Understand the JavaScript Why 

There are all kinds of languages and frameworks, so it’s almost inevitable the interviewer will ask you why you chose to learn JavaScript or if it’s your favorite language. So, refreshing your understanding of how JavaScript differs from Java or Ruby or Python, for example, is a good way to prepare for your next interview. One thing to mention is that you can define variables in JavaScript without specifying a particular type; the language does the work for you based on the value assigned to the variable. 

Understand the Virtual Destructor 

Sorry, dude, there are no destructors in JavaScript. This is a classic trick interview question. There are no functions called to free objects in JavaScript; instead, there’s a garbage collector automated to run at intervals. That cleans up objects and memory you’re not using. Other languages like C++ have virtual destructors, but JavaScript does not. 
Understand the Difference Between Context and Scope 

Like the virtual destructor question, this one is designed to trip you up. You’ll hear the two words used almost interchangeably but they mean different things. Context is the value of “this”—or, the object that owns the real-time executing code. Scope is the access of a variable when a function is invoked. Both are uniquely flexible in JavaScript and both always confuse developers. But scope is function base and context is object based. 

What Are the Benefits of Adding ‘Use Strict’? 

Adding ‘use strict’ at the beginning of a JavaScript source file is a good way to enforce tighter parsing and error handling when you run your code. It’s a best practice because the code errors that break your application will fail silently during runtime. Adding ‘use strict’ generates errors or throws exceptions, which is perfect when testing your code. It makes debugging a whole lot easier and prevents accidental global variables. It also will disallow duplicate parameter values that will cause bugs. Generally, adding ‘use strict’ is a smarter way to write in JavaScript and can save you a ton of time tracking down what’s broken. 

Define Two Programming Paradigms That Are Important for JS Developers 

JavaScript supports object-oriented programming (OOP) with prototypal inheritance along with imperative/procedural programming.  

The Custom Group of Companies works hands-on with new candidates to help prepare them for the interviewing process.

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