Top Javascript Questions & Practice
Master 50+ essential Javascript questions ranging from core fundamentals to senior-level real-world scenarios.
Junior Fundamentals — Question 1
Core language fundamentals.
Which keyword declares a block-scoped variable that can be reassigned?
Junior Fundamentals — Question 2
Core language fundamentals.
What is the result of `typeof null`?
Junior Fundamentals — Question 3
Core language fundamentals.
Which value is falsy?
Junior Fundamentals — Question 4
Core language fundamentals.
What is the main difference between `==` and `===`?
Junior Fundamentals — Question 5
Core language fundamentals.
What does `const` prevent?
Junior Fundamentals — Question 6
Core language fundamentals.
Which declaration is function-scoped?
Junior Fundamentals — Question 7
Core language fundamentals.
What does `Object.is(NaN, NaN)` return?
Junior Fundamentals — Question 8
Core language fundamentals.
Which operator should generally be used when you want a fallback only for null or undefined?
Junior Fundamentals — Question 9
Core language fundamentals.
What does `typeof 10n` return?
Junior Fundamentals — Question 10
Core language fundamentals.
Which statement about arrays is correct?