react-doctor/js-cache-property-access

Hoist the deep member access into a const at the top of the loop body: `const { x, y } = obj.deeply.nested`

• Category: Performance
• Severity: warn
• Source: oxlint-plugin-react-doctor
• Framework: global
• Enabled when: always

Validation prompt

Use this to decide whether a fired diagnostic is real or a false positive.

The rule fires when the same non-computed deep member chain (depth >= 2 dots, e.g. obj.a.b.c) is read 3 or more times inside one loop body, counting only the deepest reference per chain. False positive if any segment is a getter with intentional side effects, the nested object reference is reassigned mid-loop, or the chain crosses a Proxy you want to re-trigger.

Fix prompt

Use this once validation confirms the diagnostic is real.

Hoist at the top of the loop body: const { x, y } = obj.deeply.nested; or const target = obj.deeply.nested; then reuse target.x / target.y. Skips re-walking the prototype chain and re-invoking any getters along the path on every iteration. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment

Related rules

More Performance rules from the rules reference:

• react-doctor/js-cache-storage: Cache repeated `localStorage`/`sessionStorage` reads in a local variable — each access serializes/deserializes
• react-doctor/js-combine-iterations: Combine `.map().filter()` (or similar chains) into a single pass with `.reduce()` or a `for...of` loop to avoid iterating the array twice
• react-doctor/js-early-exit: Add an early `return` / `continue` to flatten deep nesting and short-circuit when the predicate is already known
• react-doctor/js-flatmap-filter: Use `.flatMap(item => condition ? [value] : [])` — transforms and filters in a single pass instead of creating an intermediate array
• react-doctor/js-hoist-intl: Hoist `new Intl.NumberFormat(...)` to module scope or wrap in `useMemo` — Intl constructors allocate dozens of objects per locale lookup