react-doctor/prefer-module-scope-static-value

Hoist the static array/object literal to module scope above the component: const FILTER_OPTIONS = ["all", "active", "done"]; function App() { ... }

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

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Fires on a VariableDeclarator with an Identifier id whose initializer (after stripParenExpression) is an ArrayExpression or ObjectExpression literal, declared directly in a component/hook body scope (enclosingComponentOrHookScope, which walks to the nearest enclosing function and stops there), where hasComponentLocalReferences finds NO reference resolving to a symbol inside the component bodyScope, and isBindingMutatedAfterInit finds no mutation. Module-level imports/globals captured in the value still count as hoistable (RANKED_ROLES = [ROLES.admin, ROLES.editor] fires). It deliberately fires inside memo()/forwardRef()-wrapped components and even when the binding is only READ via .includes/.find/.map/property access/index reads (read-only methods are excluded from MUTATING_RECEIVER_METHOD_NAMES). Does NOT fire on: primitives (const MAX = 100); empty accumulator literals that get mutated (const parts = []; parts.push(...)); values inside useMemo/useCallback callbacks or event handlers (the nearest enclosing function is the callback, not the component); values already at module scope or in lowercase/non-component helpers (makeApi); arrays/objects containing inline function expressions, since hasComponentLocalReferences flags any nested Arrow/FunctionExpression as a local capture (const handlers = [() => ..., () => ...]); bindings the detector already sees as mutated after init via isMutationContext — rebinding (OPTS = ...), property reassignment (CONFIG.mode = ...), index assignment (OPTS[0] = ...), delete CONFIG.x, or a mutating method call (OPTS.push(...), map.set(...)); and PascalCase non-hook factory functions that return a plain object literal (e.g. a ProseMirror plugin factory like AIHandlePlugin), which enclosingComponentOrHookScope drops via doesFunctionReturnsObjectLiteral because they are called once and never re-render. The only genuine residual false positives a reviewer should suppress: the binding IS mutated but through a path isMutationContext cannot resolve — an alias (const a = OPTS; a.push(x)) or by being passed into a function that mutates it in place — so hoisting would create a shared mutable module singleton; or the literal actually closes over local state/props/inner-function bindings that scope analysis failed to resolve, making the hoist break semantics.

Fix prompt

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Move the literal out of the component to module scope (above the component, after imports) since it references no local state: change function App() { const FILTER_OPTIONS = ["all","active","done"]; ... } to const FILTER_OPTIONS = ["all","active","done"]; function App() { ... } so the array/object is allocated once and memoised consumers receive a stable reference across renders. Only hoist if the binding is genuinely read-only after init across every path including aliases and functions it is passed to; if it is mutated in place, leave it in the component or refactor the mutation away (e.g. build the value from props/state during render) before hoisting.