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9 Interview Questions Every Senior React Developer Should Know

Christopher Clemmons 115

As a React developer, you’ll eventually experience the urge to take that next large step into a senior role. Many of us stay stuck as a junior or mid-level developer, even as we get more experienced.

Of course, experience comes with time but some of you may have the mindset of a senior developer but not studying the required topics.

This blog will not contain tutorials but a general overview of the kind of answers you should give.

Here are some very common interview questions you may be asked while interviewing for a senior -level position as a React developer.

1. Can you describe a situation where you had to optimize a React application to improve its performance? How did you go about doing this?

As a candidate for a senior React developer position, you will be expected at times to know how to optimize a React app for better performance. Understanding React’s lifecycle and hooks can help with this. Some ways of optimizing a React app’s performance can include

  • Avoiding unnecessary rerenders
  • Using a UID (unique identifier) when rendering lists
  • Using hooks such as useMemo and useCallback to memoize expense functions
  • Mounting checks.

Read my blog about using mounting checks to prevent rerenders in React here

2. How do you handle state management in a large React application?

There are two types of state in React. Localized and global state. The localized state is exclusive to the scope of a React component. The global state can be accessed by any of your components. Some common libraries for managing state in a large react application include

When to use state?

Imagine that you are building a to-do list app in React. You want to keep track of the list of to-do items that the user has entered, as well as a boolean value…