Coding⏱️ 2 min read📅 2026-05-30

How to Fix: ReactJS giving error Uncaught TypeError: Super expression must either be null or a function, not undefined

Error in ReactJS code due to undefined super expression.

Quick Answer: {

To fix the 'Uncaught TypeError: Super expression must either be null or a function, not undefined' error in ReactJS, you need to ensure that your class components are extending from the React.Component class.

⚠️ Common Causes

  • Missing or incorrect inheritance in class components.

✅ Best Solutions to Fix It

Method 1: Inheriting from React.Component

  1. Step 1: Ensure that your class components are extending from the React.Component class.

Method 2: Using ES6 Classes

  1. Step 1: Use the class keyword to define your React component class.

✨ Wrapping Up

By following these steps, you should be able to resolve the 'Uncaught TypeError: Super expression must either be null or a function, not undefined' error in your ReactJS application.

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