Skip to main content

📓 React Technical Interview Questions

Congratulations! You've finished the React curriculum and you're ready to start the process of looking for work. In order to to present your understanding as clearly as possible, please make sure to have a talking point for each of the following questions. Clearly no interviewer will ask all of these questions, and depending on the job you're interviewing for, it may be that only a specific subset of these questions applies. Work smart! Curate answers to these questions, organize them into specific topics, and consult the list in ways that are specifically useful.

  • What is React and how is it different than other Javascript frameworks?
  • In what ways are components different in Angular2 and React?
  • What similarities and differences are there in how components interact with data in Angular2 and React?
  • What is a route and when do we use them?
  • What is the difference between a POST and GET request?
  • What is Git and how do we use it?
  • Explain the process (server communication) of a person browsing to and logging into a website.
  • What is a class?
  • What is an object?
  • What is a module?
  • Give an example of using an imported module AND a custom module.
  • Give an example of recursion.
  • What is Object Oriented Programming?
  • How is Object Oriented Programming different than Functional Programming?
  • Give specific examples of the implementation of these two paradigms in class.
  • What is unit testing?
  • What is integration testing?
  • What is string interpolation?
  • What is ES6 and how do we use it?
  • What is a lambda (arrow) function and how do we use it?
  • What is destructuring?
  • What is a spread operator?
  • How do local and instance variables differ?
  • Explain the rules of scope in Javascript.
  • What is REST?
  • How do we extend classes in Javascript?
  • Explain the difference between classical and prototypical inheritance.
  • When working with a Angular2, how do you decide what logic should reside in models vs. controllers?
  • Describe the workflow of writing and implementing unit tests and logic in Redux.
  • How do you use Git to manage workflow in multiple branches?
  • Explain a piece of code you're particularly proud of.
  • Explain polymorphism.
  • What is JSON and how do you parse it?
  • What's the difference between a class and an object?
  • What is HTTP and why do we use it?
  • What is the difference between a private and public class method?
  • How do you select an element from the DOM in jQuery?
  • How would you do the same thing without jQuery?
  • What is callback function?
  • What is a promise?
  • What is an observable?
  • What is middleware and how do we create a custom middleware in React?
  • Describe Arrays.
  • What kind of loops are their in JS and what are their use cases?
  • What does MVC stand for?
  • Where do each of the functional pieces of an MVC fit into a react-redux app?
  • What is a join table in SQL?
  • What is CSS?
  • What are the parts of a CSS rule?
  • Describe specificity in CSS.
  • Describe how specificity is handled uniquely in React.
  • What differences stand between modular and inline CSS in React
  • What is accessibility in web development?
  • What's the difference between =, ==, and === in JavaScript?
  • What is the difference between an undefined and undeclared variable?
  • What are the parts of a for loop?
  • What are the parts of an if statement (conditional)?
  • You've been working at X company for a couple months. One day you come it and the site is down. What do you do?
  • You clone a React project you were working on the previous day, run it in the browser, and the project won't load. What do you do?
  • You clone a React project you were working on the previous day, run it in the browser, and the conditional rendering of your components is messed up. What do you do?