Understanding How to Pass Data from Child to Parent Components in React: A Must-Know Interview Question

Introduction

If you’re a React developer actively preparing for interviews, you might have noticed a common pattern in technical interviews: “How do you pass data from a child component to a parent component?” While React is known for its unidirectional data flow (parent-to-child), there are occasions where you may need to communicate data in the opposite direction, i.e., from a child to its parent.

In this blog, we’ll explore why this pattern is commonly asked, how to implement it, and review a practical example. By the end of this article, you’ll be confident in handling this question in your next interview!

Why Interviewers Ask This Question

React follows a unidirectional data flow where data is typically passed from a parent to a child component using props. However, in real-world applications, there are scenarios where child components may need to send information back to the parent, such as when:

1. Handling form inputs where the parent needs the latest input value.
2. Triggering a state change in the parent based on user interactions in the child.
3. Notifying the parent when an event occurs…