Javascript Quiz For Intermediate Developers: Test Your Skills

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Are you an intermediate JavaScript developer looking to test your skills and knowledge? Look no further! This article is designed to provide you with a comprehensive quiz to assess your understanding of JavaScript concepts, syntax, and best practices. Whether you're preparing for a job interview, trying to improve your skills, or simply wanting to challenge yourself, this quiz is perfect for you.

The Importance of JavaScript

Before we dive into the quiz, let's quickly discuss the importance of JavaScript in modern web development. JavaScript is a versatile and widely-used language that allows developers to create dynamic, interactive web pages, web applications, and mobile applications. It's a crucial skill for any web developer to have, and is used by many popular frameworks and libraries, such as React, Angular, and Vue.js.

Quiz Instructions

The quiz consists of 20 questions, divided into four sections: Variables and Data Types, Functions and Scope, Object-Oriented Programming, and Advanced Topics. Each question has four possible answers, and you can only choose one answer per question. Take your time to read each question carefully, and good luck!

Section 1: Variables and Data Types

1. What is the difference between the let and const keywords in JavaScript?

A) `let` is used for declaring constants, while `const` is used for declaring variables. B) `let` is used for declaring variables, while `const` is used for declaring constants. C) `let` is used for declaring global variables, while `const` is used for declaring local variables. D) `let` is used for declaring local variables, while `const` is used for declaring global variables.

2. What is the output of the following code: console.log(typeof null)?

A) `object` B) `null` C) `undefined` D) `number`

Section 2: Functions and Scope

3. What is the difference between a function declaration and a function expression in JavaScript?

A) A function declaration is used for declaring functions, while a function expression is used for calling functions. B) A function declaration is used for declaring variables, while a function expression is used for declaring functions. C) A function declaration is used for declaring functions, while a function expression is used for assigning functions to variables. D) A function declaration is used for declaring global functions, while a function expression is used for declaring local functions.

4. What is the output of the following code: console.log(this) inside a function that is not an arrow function?

A) The global object (window or global) B) The function itself C) The function's prototype D) The function's context

Section 3: Object-Oriented Programming

5. What is the difference between a class and an object in JavaScript?

A) A class is an instance of an object, while an object is a blueprint for creating classes. B) A class is a blueprint for creating objects, while an object is an instance of a class. C) A class is a type of object, while an object is a type of class. D) A class is a function, while an object is a variable.

6. What is the output of the following code: console.log(Object.getPrototypeOf({}))?

A) The Object prototype B) The Array prototype C) The Function prototype D) The String prototype

Section 4: Advanced Topics

7. What is the difference between == and === in JavaScript?

A) `==` checks for value equality, while `===` checks for type and value equality. B) `==` checks for type and value equality, while `===` checks for value equality. C) `==` checks for reference equality, while `===` checks for value equality. D) `==` checks for value equality, while `===` checks for reference equality.

8. What is the output of the following code: console.log(async () => { await new Promise(resolve => { resolve('Hello World'); }); })()?

A) `Hello World` B) A Promise object C) An error D) `undefined`

And so on...

Gallery of JavaScript Concepts

FAQs

Conclusion

Congratulations on completing the JavaScript quiz! We hope you found it challenging and informative. Whether you're a beginner or an experienced developer, there's always room for improvement. Keep practicing, and don't be afraid to ask questions or seek help when needed. Good luck with your future coding endeavors!