JavaScript Interview Questions Your Guide to Success
JavaScript is the backbone of modern web development, making it a must-have skill for front-end and full-stack developers. Jobpe provides curated JavaScript interview questions, real-world scenarios, and expert tips to help you excel in your next technical interview.
javascript
- Programming
What are the different data types available in JavaScript?
JavaScript has several data types including Number, String, Boolean, Object, Undefined, Null, Symbol, and BigInt.
Explain the concept of closures in JavaScript.
Closures allow a function to access variables from an enclosing scope even after the outer function has finished executing.
What is event bubbling in JavaScript?
Event bubbling is a type of event propagation where an event starts from the deepest element and propagates up to...
How does the ‘this’ keyword work in JavaScript?
‘this’ refers to the object that is currently executing the function and its value depends on how the function is called.
What is the difference between == and === in JavaScript?
‘==’ compares values after type coercion, while ‘===’ compares both value and type without coercion.
Explain how promises work in JavaScript.
Promises represent asynchronous operations and can be in pending, fulfilled, or rejected state, allowing chaining...
What are arrow functions and how do they differ from regular functions?
Arrow functions provide a shorter syntax and do not have their own ‘this’ binding, which makes them useful in...
What is hoisting in JavaScript?
Hoisting is JavaScript's behavior of moving declarations to the top of the current scope before code execution.
Describe event delegation and its benefits.
Event delegation uses event bubbling to handle events at a higher level in the DOM, improving performance by...
How do you manage asynchronous code with async/await?
async/await allows writing asynchronous code that looks synchronous, improving readability and error handling in JavaScript.
Programming
What are the different data types available in JavaScript?
JavaScript has several data types including Number, String, Boolean, Object, Undefined, Null, Symbol, and BigInt.
Explain the concept of closures in JavaScript.
Closures allow a function to access variables from an enclosing scope even after the outer function has finished executing.
What is event bubbling in JavaScript?
Event bubbling is a type of event propagation where an event starts from the deepest element and propagates up to its parents.
How does the ‘this’ keyword work in JavaScript?
‘this’ refers to the object that is currently executing the function and its value depends on how the function is called.
What is the difference between == and === in JavaScript?
‘==’ compares values after type coercion, while ‘===’ compares both value and type without coercion.
Explain how promises work in JavaScript.
Promises represent asynchronous operations and can be in pending, fulfilled, or rejected state, allowing chaining with then() and catch() methods.
What are arrow functions and how do they differ from regular functions?
Arrow functions provide a shorter syntax and do not have their own ‘this’ binding, which makes them useful in certain contexts.
What is hoisting in JavaScript?
Hoisting is JavaScript's behavior of moving declarations to the top of the current scope before code execution.
Describe event delegation and its benefits.
Event delegation uses event bubbling to handle events at a higher level in the DOM, improving performance by reducing the number of event listeners.
How do you manage asynchronous code with async/await?
async/await allows writing asynchronous code that looks synchronous, improving readability and error handling in JavaScript.
