Javascript Logical Interview Questions
10 Common JavaScript Logical Interview Questions
JavaScript logical interview questions are focused on testing a developer's understanding of logical operations and expressions in JavaScript, as well as their ability to use them effectively in code. These questions may cover topics such as logical operators (&&, ||, !), conditional statements (if/else), truthy and falsy values, short-circuit evaluation, ternary operators, and more. Interviewers look for candidates who have a strong grasp of how logic works in programming and can demonstrate their skills through problem-solving and code analysis.
To Download Our Brochure: https://www.justacademy.co/download-brochure-for-free
Message us for more information: +91 9987184296
1 - What is the difference between == and === in JavaScript?
== is a loose equality operator, meaning it will compare values without checking the data type, while === is a strict equality operator that also checks for data type.
2) What is the difference between null and undefined in JavaScript?
Null represents an intentional absence of a value, while undefined represents an unintentional absence of a value. In other words, null is explicitly assigned by the programmer, while undefined is assigned by the JavaScript engine.
3) What is the difference between let, var, and const?
Let and var declare variables that can be reassigned, while const declares a variable with a constant value. Additionally, let and const have block scope, while var has function scope.
4) How does hoisting work in JavaScript?
Hoisting is a JavaScript mechanism where variables and function declarations are moved to the top of their scope before code execution. This allows variables and functions to be used before they are declared.
5) How do you check the data type of a variable in JavaScript?
The typeof operator is used to check the data type of a variable in JavaScript.
6) What is the purpose of the keyword “this” in JavaScript?
The “this” keyword refers to the current object and is used for method calls and object context.
7) What is a closure in JavaScript?
A closure is an inner function that has access to the variables defined in the outer function, even after the outer function has returned. This allows for data privacy and encapsulation in JavaScript.
8) What is the difference between a for loop and a for…in loop in JavaScript?
A for loop is used for iterating over a finite sequence, while a for…in loop is used for iterating over the properties of an object.
9) What is event bubbling in JavaScript?
Event bubbling is the process of propagating an event from the deepest level of the DOM tree up to the parent elements. This allows for event handlers to be triggered multiple times as it bubbles up the DOM.
10) What is a callback function?
A callback function is a function that is passed as an argument to another function and executed later. It is commonly used for asynchronous programming in JavaScript.
11) How do you handle errors in JavaScript?
Error handling in JavaScript can be done using try…catch blocks, the throw statement, or by using the JavaScript Error object.
12) What is the purpose of the “new” keyword in JavaScript?
The “new” keyword is used to create an instance of a constructor function.
13) What is the difference between a shallow copy and a deep copy?
To Download Our Brochure: Click Here
Message us for more information: +91 9987184296
A shallow copy creates a new object that references the same values as the original object, while a deep copy creates a new object with entirely new values.
14) What is a palindrome and how would you check for it in JavaScript?
A palindrome is a word or phrase that reads the same backward as it does forward. To check for a palindrome in JavaScript, we can compare the original string with the reverse of that string.
15) What is the difference between a map and a set in JavaScript?
A map is an object that stores key value pairs, while a set is a collection of unique values. Additionally, sets do not have keys and do not preserve the insertion order like maps do.
Browse our course links : https://www.justacademy.co/all-courses
To Join our FREE DEMO Session: Click Here
Contact Us for more info:
- Message us on Whatsapp: +91 9987184296
- Email id: info@justacademy.co
Automation Java Interview Questions
Laravel Interview Questions For 6 Years Experience
Java Interview Questions For Testers
