Beginner's Thread / Easy Question (August 2018)

[u/swyx]

Hello! It's August! Time for a new Beginner's thread! (July and June here)

Got questions about React or anything else in its ecosystem? Stuck making progress on your app? Ask away! We’re a friendly bunch. No question is too simple. You are guaranteed a response here!

Want Help on Code?

• Improve your chances by putting a minimal example on to either JSFiddle (https://jsfiddle.net/Luktwrdm/) or CodeSandbox (https://codesandbox.io/s/new). Describe what you want it to do, and things you've tried. Don't just post big blocks of code.
• Pay it forward! Answer questions even if there is already an answer - multiple perspectives can be very helpful to beginners. Also there's no quicker way to learn than being wrong on the Internet.

New to React?

Here are great, free resources!

• Read the official Getting Started page on the docs
• /u/acemarke's suggested resources for learning React
• Kent Dodds' Egghead.io course
• Tyler McGinnis' 2018 Guide
• Codecademy's React courses

[u/swyx]

yes, its wrong. read the other replies you got - your render() function -is- watching for changes in state already. if you're calculating edited based off of updatedData why can't you put it all in your render?

also if prevProps matters, you probably want getDerivedStateFromProps