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React Interview Questions 🔥

Pramit Marattha on November 16, 2021

Do you want to make a career change to something more lucrative? Or have you been putting in a lot of time and effort in preparation for an intervi...

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Sobin George Thomas • Nov 16 '21

@lukeshiru True. React Hooks are a complete and better replacement for Classes. But that doesn't mean we have to rewrite tens of thousands of components written as classes. Instead, we use Hooks in the new code side by side with classes. Also, I don't think React has any plan to deprecate classes. Also long as there is legacy code support, someone has to maintain them. The best example is COBOL and FORTRAN, they refuse to die. Some poor developer is surviving on them.

Source

Justin Henry • Dec 27 '21

The Legacy Code Problem is one that ultimately needs to be addressed first. Any decent Software company will take it seriously and move away from as much legacy code as possible. If you don't, you risk dependency vulnerabilities, version incompatibilities, performance bottle-necking, and increased maintenance cost just from it sitting stale for long periods of time without eyes on it. I can't tell you how many times I've been told "we have to do it this way because of legacy code" and that is not a sufficient answer to any problem. You're supposed to keep your code up to date and as clean as possible as you grow as a developer, otherwise you will end up resenting the legacy code and lose willpower to touch it.

dastasoft • Nov 19 '21

Awesome contribution! If you want to expand it further or do a part 2 maybe useMemo, useCallback and other optimization techniques will be good issues to cover.

Thanks for sharing!

Pramit Marattha • Nov 20 '21

Absolutely!! 😄

Adam Aslan • Nov 16 '21 • Edited

class User extends React.Component {
  constructor(props) {
    super(props)

    this.state = {
      message: 'Welcome to React world'
    }
  }

Also isnt talking about State like this ^ and with setstate no longer best practices?

Sobin George Thomas • Nov 16 '21 • Edited

@adamaslan Well, you should not call setState() in the constructor(). Instead, if your component needs to use local state, assign the initial state to this.state directly in the constructor.
src: reactjs.org/docs/react-component.h...

Sobin George Thomas • Nov 16 '21 • Edited

@lukeshiru Looks like the author has added a pdf of all the 300+ questions at the end.

But, I strongly agree that the author should have added React Router v6 questions. It's already been 13 days from today(17th Nov 2021) that React Router v6 has been the new stable version.

The author should also consider React Location. As it may soon kill React Router. I believe, it was last week, Tanner Linsley (the creator of React Query, React Table, React Charts, React Virtual - AKA the TanStack) released React Location.

Sobin George Thomas • Nov 17 '21

@lukestuts I strongly agree. The title should be something else. Even I was expecting a hellishly long article that can challenge my scroll bar. The author should have added all 300+ questions and answers in one article or created 10+ posts with ~30 questions each.