LESSON 2.1
When memo actually helps
Learn key techniques and workflows in React Performance Engineering.
10m
advanced
6,270 students
Overview
memo skips a re-render when props are shallow-equal. It costs a comparison on every render, so applying it everywhere makes things slower, not faster.
In this lesson you will:
- Apply memo to expensive subtrees with stable props
- Understand shallow comparison and why objects defeat it
- Recognise when restructuring beats memoising
Pro Tip
Use caching and revalidation wisely to ensure your app stays fast and data remains fresh without unnecessary requests.