Planet Spark Software Engineer Interview Questions and Answers

Coding test around front end using react

Normal Aptitute test with logical reasoning.

Q1. Q1 difference between let and const
Ans. 
let is mutable and can be reassigned, const is immutable and cannot be reassigned
• let allows reassignment of values, const does not

• const must be initialized with a value, let can be declared without a value

• const is block-scoped, let is function-scoped
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Q2. Q2 what are closures?
Ans. 
Closures are functions that have access to variables from their containing scope even after the parent function has finished executing.
• Closures allow functions to maintain access to variables from their parent scope

• They are created when a function is defined within another function

• Closures are commonly used in event handlers and callbacks
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Q3. Q3. What is typeof null
Ans. 
typeof null returns 'object' in JavaScript.
• typeof null is 'object' in JavaScript

• This is a historical bug in JavaScript that has not been fixed for backward compatibility

• Example: console.log(typeof null) will output 'object'
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Q1. Q1. Find palindrome strings in an array of strings.
Ans. 
Finding palindrome strings in an array of strings.
• Iterate through each string in the array.

• For each string, check if it is equal to its reverse to determine if it is a palindrome.

• Store palindrome strings in a separate array or print them out.
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Q2. Q2. Explain debouncing with example.
Ans. 
Debouncing is a technique used to limit the rate at which a function is called.
• Debouncing is used to prevent multiple rapid calls to a function, typically in response to user input.

• It involves setting a delay before allowing the function to be called again.

• Example: Debouncing a search input field to only trigger the search function after the user has stopped typing for a certain period.
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Q1. What is react, diff between react and angular, deep copy shallow copy, hoisting, diff between props and state
Ans. 
React is a JavaScript library for building user interfaces. It is different from Angular in various ways.
• React is a library while Angular is a framework

• React uses virtual DOM while Angular uses real DOM

• React is more flexible and easier to learn than Angular

• Deep copy creates a new object with the same values while shallow copy creates a new reference to the same object

• Hoisting is a JavaScript mechanism where variables a...read more
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Q2. Implement custom hooks and array flat method
Ans. 
Implement custom hooks and array flat method
• Custom hooks are reusable functions that allow you to extract component logic into reusable functions

• Array flat method is used to flatten an array of nested arrays into a single array

• To implement custom hooks, create a function that uses the useState and useEffect hooks

• To implement array flat method, use the reduce method to flatten the array
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Q1. Check if string is palindrome
Ans. 
Check if a string is the same forwards and backwards
• Iterate through the string from both ends and compare characters

• Use built-in functions like reverse() to check for palindrome

• Ignore spaces and punctuation when checking for palindrome
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Two dynamic programming challenges at the hard level on LeetCode and 10 medium-level SQL challenge.

Python technical SQL basic