`react-doctor/no-spread-props-over-defaults-clobbers-with-undefined`

Spread props over defaults can clobber with undefined

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

Validate the diagnostic

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

Confirm the reported code matches react-doctor/no-spread-props-over-defaults-clobbers-with-undefined. 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

interface Props {
  width?: number;
}
const defaults = { width: 100 };
const Panel = (props: Props) => {
  const merged = { ...theme, ...defaults, ...props };
  return merged.width * 2;
};

Corrected pattern

interface Props {
  width?: number;
}
const defaults = { width: 100 };
const Panel = (props: Props) => {
  const merged = { ...theme, ...defaults, ...props };
  return (merged.width ?? 100) * 2;
};

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-spread-props-over-defaults-clobbers-with-undefined diagnostic in the current repository. Required change: - An explicit undefined prop can overwrite a default. Reapply defaults with ?? at the merge or use site, or remove undefined keys before spreading props.

Reference transformation:Before:

interface Props {
  width?: number;
}
const defaults = { width: 100 };
const Panel = (props: Props) => {
  const merged = { ...theme, ...defaults, ...props };
  return merged.width * 2;
};

After:

interface Props {
  width?: number;
}
const defaults = { width: 100 };
const Panel = (props: Props) => {
  const merged = { ...theme, ...defaults, ...props };
  return (merged.width ?? 100) * 2;
};

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. - Confirm this rule is enabled for the project: react. 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-stale-timer-ref: Cleared timer ref keeps the stale id
react-doctor/no-static-motion-config-never: MotionConfig always ignores reduced motion
react-doctor/no-string-false-on-boolean-attribute: String true/false on a boolean attribute
react-doctor/no-string-refs: Disallow legacy string refs like ref='node' — use createRef, useRef, or callback refs.
react-doctor/no-this-in-sfc: Use the function's `props` parameter instead of `this.props` in stateless function components.

react-doctor/no-spread-props-over-defaults-clobbers-with-undefined