Thread by @swapnakpanda

JavaScript Interview Questions

⇩

Series: 2️⃣
Level: Beginner
Topics:

➊ Basics about Arrays
➋ Array Properties
➌ Array Methods
➍ Looping through Arrays
➎ Array related Operators
➏ Common Array Operations
➐ Comparison of Terms

🚥 Disclaimer

⬖ The questions covered here are mostly conceptual
⬘ I never claim only these type of questions are/should be asked during interviews
⬗ For interviews, you should have fundamentals strong. And you should be able to provide solutions to practical problems.

➊ Basics about Arrays

➀ Describe an Array in JS perspective?
➁ What is Array Literal?
➂ Explain about +ve and -ve indexes in an Array?
➃ What is Array's type?
➄ What is an Array-Like object?
➅ Which Array operations can be done on an Array-Like object?

➆ What is a sparse array and, a dense array?
➇ How to detect a sparse array?
➈ How is a sparse array formed?
➉ Describe the looping behaviour for a sparse array.

➋ Array Properties

➀ How to find size of an array?
➁ How to create an Array of a given size?
➂ Is array in JavaScript static sized or, dynamic sized?
➃ Is "length" a mutable property?
Or,
➃ Can "length" of an Array be changed manually?

➄ What does happen when "length" is reduced?
➅ What will happen when "length" is increased?
➆ How to remove elements from the end of an array by manipulating the "length" property?

➌ Array Methods

➀ Which methods of Array.prototype accepts negative indexes?
➁ How to do deep level flat operation?

✪Which method will you use to

➂ find the first element of an array that matches a condition
➃ find if an array has an element that matches a condition

➄ fetch an element using negative index
➅ insert multiple elements at the end of an array
➆ insert multiple elements at the starting of an array
➇ remove multiple elements at the starting of an array
➈ remove multiple elements at the end of an array

➉ insert multiple elements at an index after removing multiple elements from the same index
➀➀ populate all indexes with the same value
➀➁ retrieve a sub-array between 2 indices
➀➂ copy an array
➀➃ convert an array-like object to array

➍ Looping through Arrays

➀ Between for...in and for...of, which is more suitable for an Array to loop through?
➁ Mention all Array.prototype methods which loop through the array.
➂ How is a sparse array looped? Describe for different looping methods.

➎ Array related Operators

➀ What is destructuring assignment for arrays?
➁ What is rest parameter inside destructuring assignment?
➂ Which is valid? [a, b, ...c], [a, ...b, c]
➃ Explain how spread operator operates.
➄ Swap 2 numbers using Array Destructuring.

➏ Common Array Operations

➀ Insert an element into an array at starting/ending/any position by not mutating the original.

➁ Update an element of an array at starting/ending/any position by not mutating the original.

➂ Delete an element from an array at starting/ending/any position by not mutating the original.

➃ Insert and delete an element into/from an array at starting/ending/any position by using splice()

➄ Create a copy of an array using spread operator syntax.

➅ Merge 2 or, more arrays using concat()
➆ Merge 2 or, more arrays using flat()
➇ Merge 2 or, more arrays using spread operator syntax
➈ Find sum of all elements in an array using reduce()
➉ Shuffle elements of an array

➐ Comparison of Terms

Mention the difference between

➀ "Array()" and "new Array()"
➁ Single and Multiple parameter Array()
➂ Array.of() and Array.from()
➃ find() and filter()
➄ findIndex() and indexOf()
➅ includes() and some()
➆ some() and every()

➇ map() and flatMap()
➈ slice() and splice()
➉ forEach() and map()
➀➀ forEach() and for...of
➀➁ shift() and pop()
➀➂ unshift() and push()
➀➃ reduce() and reduceRight()

⚠️ Repost Notice ⚠️

⬖ Though this is my original work, it was previously posted in [CHIRPBIRDICON]

⬘ Many questions have been taken from the original 🧵

⬙ If you liked these questions and do feel others might learn from it, please support.

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