React Render vs Commit Phase Explained (How React Actually Updates UI)
What actually happens after React re-renders a component?
Most developers know that React "renders", but very few understand what happens next.
In this video, we break down the two most important phases in React:
Render Phase (calculation)
Commit Phase (DOM updates)
You’ll learn:
What React does during the render phase
When React actually updates the DOM
Why console logs run before UI updates
Why side effects should NOT run during render
Why useEffect runs after rendering
The difference between render and DOM updates
How this connects to React Strict Mode
If you've ever been confused about:
"Why is my code running before the UI updates?"
or
"Why does useEffect run later?"
This video will give you a clear mental model.
This is part of my React fundamentals series where I explain React concepts visually and in a way that actually sticks.
Topics covered:
React render phase
React commit phase
React rendering lifecycle
React internals
useEffect timing
React interview questions
#react #reactjs #javascript #frontend #webdevelopment