‘Cannot read properties of undefined’ in React: fix it at the data layer, not with ?.
The most common JavaScript crash in React apps almost always means one thing: you rendered before the data existed. Loading states, optional…
Appesto
Tag: debugging
‘Objects are not valid as a React child’: what it means and 6 ways it happens
React can render strings and numbers - not objects. This error fires the moment JSX receives one, and the culprit is usually…
‘Invalid hook call’ in React: every cause and how to fix each one
Hooks can only be called inside a function component - but you knew that and you're still getting the error. Here's the…
How to fix the React useEffect infinite loop (and ‘Too many re-renders’)
The #1 React question on Stack Overflow, solved properly: why useEffect loops forever, what 'Too many re-renders' actually means, and the dependency-array…
Port already in use? How to find and kill the process on any port (Windows, macOS, Linux)
EADDRINUSE: address already in use is the most common dev-server error there is. Here's how to find and kill the offending process…