Memoize only expensive work

Use memoization for costly derived values, not as decoration around every expression.

Code example

Copy, adapt, and ship.

Read the numbered lines, copy the complete snippet, then adjust the values for your project.

React snippet

01const visibleRows = useMemo(() => {02  return rows03    .filter((row) => row.status === activeStatus)04    .sort((a, b) => b.score - a.score);05}, [rows, activeStatus]);

Production-ready starting point5 lines · copy with one click

Why this matters

The production reason.

01
Memoization is useful when a calculation is expensive or when a stable reference prevents a costly child render.
02
Using useMemo everywhere adds dependency noise and can hide simpler data-flow problems.
03
Measure or at least identify the expensive operation before adding memoization.

Platform notes03

How it holds up outside a demo.

ReactMemoize filtered, sorted, or grouped lists when they are large.
TanStack TableMemoize column definitions so the table does not rebuild constantly.
Next.jsDo heavy data shaping on the server when the browser does not need to own it.