Cannot update component while rendering React

Why This Happens

In React, you set state in another component during render. This is one of the most common React errors developers encounter. Understanding the root cause helps you fix it quickly and prevent it from recurring.

The Problem

function Parent() {
  return <Child onChange={setParentState} />;
}
function Child({ onChange }) {
  onChange('new'); // During render!
}

The Fix

function Child({ onChange }) {
  useEffect(() => {
    onChange('new');
  }, []);
}

Step-by-Step Fix

1. 1

   Identify the error

   Look at the error message: Cannot update a component while rendering. This tells you exactly what went wrong.

2. 2

   Find the cause

   Check the stack trace to find which line of your React code triggered this error.

3. 3

   Apply the fix

   Use the corrected code pattern shown above. Test to confirm the error is resolved.