Day 9 of 14 30 minuseRefuseMemomemo
Use useRef to reach DOM elements and to keep values that don't trigger re-renders. Then learn when React re-renders, and how memo, useMemo and useCallback skip unnecessary work, plus when not to bother.
By the end of today you can
- Focus inputs and measure elements with a DOM ref
- Keep mutable values like timer ids in a ref
- Explain when and why components re-render
- Skip work with useMemo, memo and useCallback
- Decide when optimisation is worth it
What's inside
- 5 sections
- 3 diagrams and mind maps
- 3 code examples you can run
- 5-question quiz
- 1Refs to DOM elements
- 2Refs for values that don't affect the screen
- 3When does React re-render?
- 4Skipping work: useMemo, memo and useCallback
- 5When to optimise
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