react-hooks-js/globals

Validates against assignment/mutation of globals during render, part of ensuring that [side effects must render outside of render](https://react.dev/reference/rules/components-and-hooks-must-be-pure#side-effects-must-run-outside-of-render)

Validation prompt

Confirm the detector match and collect the required evidence before deciding whether an edit is warranted.

Fires on assignments or mutations to module-scope let/var bindings, frozen const-object properties, or window/globalThis/document.X writes during the synchronous body of a component or hook: e.g. let renderCount; renderCount++ at the top of a component, or window.user = id mid-render.

Suppress when: the mutation lives inside a useEffect, event handler, or async callback rather than executing during render itself.

Evidence boundary

The diagnostic proves only that the detector’s modeled source pattern matched. It does not prove runtime impact, product intent, rendered failure, or that one remediation is correct.

Establish the environment, repository policy, exceptions, and required rendered or runtime evidence before deciding the occurrence.

Record one outcome:

• Confirmed failure: The required evidence establishes the violation.
• Rejected: A documented exception or false-positive predicate applies.
• Needs evidence: Named evidence can still be collected.
• Unavailable: Required evidence cannot be collected in this run.
• Waived with evidence: An authorized, scoped exception applies to an established failure.
• Observation: The review records an optional tradeoff without claiming a defect.

A waiver records its scope, authority, evidence, and review condition. It is not a pass or false positive.

Default severity is registry metadata. Use the occurrence’s JSON severity after repository configuration when ordering real findings.

Fix prompt

Apply this candidate correction only after the required evidence confirms the risk.

Move mutable per-component state into useState/useReducer (or useRef for non-rendering scratchpads); move DOM and window writes into useEffect (or useLayoutEffect when the write must precede paint, e.g. document.title). For cross-component values, lift to context via createContext + useContext. Globals mutated during render break Fast Refresh, StrictMode double-invocation, and the React Compiler. See https://react.dev/reference/eslint-plugin-react-hooks/lints/globals

Repository-wide copy prompt

Use this repository-wide prompt only after validating each occurrence. For one occurrence, use the guidance above.