JavaScript is a dynamic programming language that is essential to the creation of websites. The ability to add interactivity and improve the user experience has made JavaScript an indispensable tool for developing contemporary websites and web applications. It enables programmers to alter webpage components, manage events, and communicate with the browser's Document Object Model (DOM) to produce dynamic and responsive user interfaces. A thorough understanding of JavaScript is crucial for new graduates who want to start a career in web development. Not only is it essential to understand the language's fundamentals, but it is also important to be ready for any interview questions that might be asked during the hiring process. Understanding common JavaScript interview questions can help freshers showcase their knowledge and problem-solving skills, demonstrating their suitability for entry-level web development roles. So let us explore the topics frequently covered in interviews and dive into the world of JavaScript interview questions for beginners to equip you better to face any challenges that may arise.
What are variables? Why are they used?
A named container used to store values is known as a variable. A piece of data we may need to refer to more than once can be saved in a variable for future use or modification. A variable's value in JavaScript can be any JavaScript data type, such as a number, string, or object.
The idea of a variable itself can be demonstrated using var.
// Give the username identifier the string value "Arun."
var username = "Arun";
There are several components to this statement:
creating a variable declaration using the var keyword
The variable name (or identifier), username
The assignment operation is symbolized by the syntax =.
The value being assigned, Arun."
Now we can use usernames in the code. JavaScript will remember that the username represents the string value run.
if (username === "Arun") {
console.log(true);
}
Output
true
Variables can represent any JavaScript data type, as was already mentioned. In this example, we will declare variables with string, number, object, Boolean, and null values.
// Assignment of various variables
var name = "Arun";
var spartans = 100;
var kingdoms = [ "chola", "chera", "pandya" ];
var success = true;
var nothing = null;
Explain the concept of closures in JavaScript?
Closures are a powerful feature in JavaScript that allows functions to retain access to variables from their outer (enclosing) scope even after executing the external process. This means inner parts can "remember" and access variables from their parent function's scope. Closures are commonly used to create private variables and to implement data encapsulation and information hiding in JavaScript. Understanding closures is crucial for writing modular and maintainable code.
What are the ES6 arrow functions?
Generally speaking, arrow functions are denoted by an equals sign followed by a more significant sign: \=>. An arrow function is a specific kind of function expression that is always anonymous.
arrowFunction.js
// Define multiply function
const multiply = (x, y) => {
return x * y;
}
// Invoke function to find product
multiply(20, 2);
Output
40
We use the \=> arrow to denote a function rather than the word "function" in writing. it functions otherwise similarly to a regular function expression.
The parentheses may not be used if there is only one parameter. Since we are only squaring x in this example, only one number must be passed as an argument. It does not include the parentheses.
// Define a square function
const square = x => {
return x * x;
}
// Invoke function to find product
square(7);
Output :
49
The syntax can be further condensed using arrow functions in these examples since they only use return statements. Curly brackets where the return statement can be skipped in cases where a function only returns a single line, as shown in the example below.
// Define square function
const square = x => x * x;
// Invoke function to find product
square(8);
Output:
64
Conclusion:
By familiarising yourself with these intermediate JavaScript interview questions, you'll be well-prepared to showcase your knowledge and skills during the interview process. Remember to understand the concepts and be able to clearly explain them, in addition to knowing the answers. If you want to learn Javascript in a structured way, go to SkillSafari. You can learn how to create a web application from the ground up and create a personalized portfolio while receiving a 100% placement guarantee.