Quiz

Here are 50 multiple-choice questions related to Functional Programming in JavaScript, covering Pure Functions and Immutability, Map, Filter, Reduce, and other Array Methods, Declarative vs. Imperative Programming, Lazy Evaluation and Infinite Sequences, and Monads, Functors, and Other FP Concepts. Each question includes a detailed explanation of the correct answer. Pure Functions and Immutability Map, Filter, … Read more

1. What is the output of the following code? console.log(typeof null); A) “object”B) “null”C) “undefined”D) “boolean” Answer: A) “object” 2. How can you create an immutable object in JavaScript? A) Object.freeze(obj)B) Object.seal(obj)C) Object.preventExtensions(obj)D) Object.immutable(obj) Answer: A) Object.freeze(obj) 3. What does the reduce method do? A) Iterates over an array and returns a new arrayB) Iterates … Read more

1. What is a closure in JavaScript? Explanation: A closure is a function that retains access to its outer scope’s variables even after the outer function has returned. This allows the inner function to maintain a reference to the variables in its enclosing scope. 2. How does JavaScript handle asynchronous operations? Explanation: JavaScript handles asynchronous … Read more

JavaScript is a dynamic and powerful language that is essential for web development. Here are 50 more multiple-choice questions with detailed explanations to help you further enhance your knowledge and skills. Question 1 What will the following code output? console.log([] == []); A) trueB) falseC) undefinedD) Error Answer: B) false Explanation: In JavaScript, two array … Read more

Question 1 What will be the output of the following code? console.log(typeof null); A) “null”B) “undefined”C) “object”D) “number” Answer: C) “object” Explanation: In JavaScript, typeof null returns “object”. This is a well-known bug in JavaScript that exists for legacy reasons. Question 2 What is the output of the following code? console.log(0 == ‘0’); A) trueB) … Read more

Question 11 What will the following code output? console.log(1 + “2” + “2”); a) 5b) “32”c) “122”d) NaN Answer: c) “122” Explanation: When adding a number to a string, JavaScript performs string concatenation. 1 + “2” results in “12”, and then “12” + “2” results in “122”. Question 12 What is the output of the … Read more

Question 1 What is the output of the following code? console.log(typeof NaN); a) “number”b) “string”c) “undefined”d) “NaN” Answer: a) “number” Explanation: In JavaScript, NaN (Not-a-Number) is actually of the type number. This is a special value that results from operations that don’t yield a valid number. Question 2 What does the following code snippet do? … Read more