defaultProps deprecated ⚛️ React

Warning: Support for defaultProps will be removed from function components in a future major release.

A function component (often inside a library) uses Component.defaultProps.

Seen on: React

Meaning

React 18.3 warns; React 19 removes defaultProps for function components. Use JavaScript default parameters instead.

Common causes

  • Your components using defaultProps
  • Old library versions using defaultProps

⚡ Quick fix

  1. Use default parameters: function Btn({ size = 'md' })
  2. Upgrade libraries

Detailed fix by platform

React

  1. function Avatar({ size = 40, alt = '' }) { … }

How to diagnose

  1. Source — Your code or a library?
  2. Recent change — Did it start after a deploy, upgrade, or configuration change? Compare with the last working version.

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