Besides props and state, every value used in a component should...

Besides props and state, every value used in a component should...

• A. Values should stay the same.
• B. Always stay exactly the same.
• C. They should be stored in a ref.
• D. They should be computed in render.

Answer: (B)

In a component, you want predictability around the values you use for rendering. Values that aren’t props or state should generally stay stable from one render to the next, so the UI remains consistent and React can optimize efficiently. That’s why many of these non-prop, non-state values are treated as constant for the component’s lifetime, unless there’s a reason to update them. If a value truly needs to persist without causing a re-render when it changes, you’d store it in a ref. This keeps the value around across renders without triggering updates. If a value should reflect changes in props or state, you derive it from those sources or manage it with state. For simple, inexpensive computations, calculating in render is fine; for expensive work, you’d memoize or derive it to avoid repeated work. So the emphasis is on stability for values that aren’t driven by props or state, which aligns with keeping them effectively the same across renders, while still allowing updates when their actual sources (props/state) change.

In a component, you want predictability around the values you use for rendering. Values that aren’t props or state should generally stay stable from one render to the next, so the UI remains consistent and React can optimize efficiently. That’s why many of these non-prop, non-state values are treated as constant for the component’s lifetime, unless there’s a reason to update them.

If a value truly needs to persist without causing a re-render when it changes, you’d store it in a ref. This keeps the value around across renders without triggering updates. If a value should reflect changes in props or state, you derive it from those sources or manage it with state. For simple, inexpensive computations, calculating in render is fine; for expensive work, you’d memoize or derive it to avoid repeated work.

So the emphasis is on stability for values that aren’t driven by props or state, which aligns with keeping them effectively the same across renders, while still allowing updates when their actual sources (props/state) change.