Progressive hydration
React chapter 110 · patterns.dev · Progressive Hydration · source: https://www.patterns.dev/react/progressive-hydration
The problem
The whole page hydrates up front: below-the-fold charts, a hidden modal, a date picker. INP and TBT pay for widgets the user has not seen. Streaming HTML (109) still ships that JS on the critical path.
The pattern that fixes it
Hydrate in priority order: above-the-fold now; below-the-fold when visible (IntersectionObserver); modals on interaction (100). RSC with no client JS hydrates nothing. Astro/Qwik name this client:visible / client:idle.
Keep learning
- Previous: Streaming SSR
- Next: Selective hydration
- Related: Higher-order component
- Related: Container / presentational
- Related: Static rendering (SSG)
- Related: Incremental static (ISR)
- Related: Streaming SSR
- Related: Selective hydration
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