`react-doctor/no-mutating-array-method-on-prop-or-hook-result`

In-place array mutation on a prop or hook result

Category: Bugs
Severity: warn
Source: oxlint-plugin-react-doctor
Framework: global
Enabled when: always
Default: Enabled

Validate the diagnostic

Confirm the reported code matches this rule before you edit it.

Confirm the reported code matches react-doctor/no-mutating-array-method-on-prop-or-hook-result. Compare it with the Before example and verify the same API, framework, and execution context. Treat it as a false positive only when one of those conditions differs.

Compare the code

The corrected pattern shows a focused way to address the diagnostic.

Reported pattern

function useTrim(items) {
  const rows = useContext(RowsContext);
  useEffect(() => {
    return () => {
      rows.splice(0, 1);
    };
  }, [rows]);
}

Corrected pattern

function useTrim() {
  const setRows = useContext(RowsDispatchContext);
  useEffect(() => {
    return () => {
      setRows((currentRows) => currentRows.slice(1));
    };
  }, [setRows]);
}

How to fix

Use the corrected pattern as a reference. Preserve behavior that the rule does not require you to change.

Copyable fix prompt

Copy this self-contained prompt into your coding agent after you confirm the diagnostic.

Fix every confirmed react-doctor/no-mutating-array-method-on-prop-or-hook-result diagnostic in the current repository. Required change: - sort, reverse, and splice mutate in place, so calling them on a prop or hook result corrupts shared state. Use the immutable toSorted/toReversed/toSpliced, or copy the array first ([...array].sort()) when targeting pre-ES2023 runtimes.

Reference transformation:Before:

function useTrim(items) {
  const rows = useContext(RowsContext);
  useEffect(() => {
    return () => {
      rows.splice(0, 1);
    };
  }, [rows]);
}

After:

function useTrim() {
  const setRows = useContext(RowsDispatchContext);
  useEffect(() => {
    return () => {
      setRows((currentRows) => currentRows.slice(1));
    };
  }, [setRows]);
}

Constraints: - Confirm the reported code matches the Before pattern. - Make the smallest change that fixes the root cause. - Preserve behavior and interfaces unrelated to this diagnostic. - Reuse existing project components, utilities, and conventions. - Do not introduce render-phase side effects, render-phase state updates, or Hooks rule violations. - Adapt identifiers and framework details instead of copying blindly. - Do not disable the rule or suppress matching code. Verification: - Run focused tests for the changed behavior. - Run React Doctor and confirm this diagnostic no longer appears. - Report the files changed and any checks you could not run.

More Bugs rules from the rules reference:

react-doctor/no-mutating-reducer-state: Return a new reducer state object/array/collection instead of mutating the current state and returning the same top-level reference.
react-doctor/no-namespace: Drop the namespace and use a plain (Pascal-cased) component or DOM tag.
react-doctor/no-nested-component-definition: Move to a separate file or to module scope above the parent component
react-doctor/no-non-literal-selector-query-without-try-catch: Unguarded querySelector with href-derived selector
react-doctor/no-non-null-assertion-on-maybe-undefined-result: Non-null assertion on a maybe-undefined result

react-doctor/no-mutating-array-method-on-prop-or-hook-result