Table of Contents
Q4. What is the primary difference between var and let?
Q5. What does the isNaN function do?
Answer – The isNaN function returns true if an argument is not a number. The function returns false if it is.
Q6. What is the difference between undeclared and undefined variables?
Answer – Undeclared variables do not exist in a program. A runtime error occurs if the program attempts to read the value of an undeclared variable.
Undefined variables are declared in the software but do not have any assigned value. If the program reads the value of an undefined variable, it returns to the original value.
Q7. What is a callback?
Q8. How does TypeOf Operator function?
Answer – TypeOf Operator is primarily used to receive the data type of its operand. The operand can be a data structure such as an object, function, or variable.
Q9. What is hoisting?
Q10. Name 3 types of Error Name values.
Answer – 3 types of Error Name values include-
- URI Error
- Reference Error
- Eval Error
Q12. What is the Typed language?
Answer – The Typed language has values that don’t associate with variables. The two types of values associated are-
Q13. What is the key difference between null and undefined?
Answer – Undefined is a variable that is declared but does not have an assigned value. Null, on the other hand, has an assigned value.
Q15. What is the key difference between local storage and session storage?
Answer – In local storage, the data is not sent to the server reversely for each request. This lessens the traffic between the server and the client. In session storage, the data stored immediately clears when the page session ends.
Q16. How are first-class functions defined?
Answer – First-class functions can either be-
- Returned as values from other functions
- Stored in a variable
- Passed as arguments to other functions
- Do-While Loops
Q19. What function does the delete operator perform?
Answer – The delete operator deletes a property, as well as its value.
- Preparing for interviews with the 20 listed questions and answers can highlight your knowledge & skills and help you stand apart from the crowd.
We hope you found this blog informative. Don’t forget to comment below and share your thoughts! You can also get in touch with us if you have any doubts.
Liked this blog? Read: Java Games | 8 Best books aspiring Java developers must know about!
Q2. What is front-end web development?