`react-doctor/react-router-loader-parallel-fetch`

Independent loader work runs sequentially

Category: Performance
Severity: warn
Source: oxlint-plugin-react-doctor
Framework: global
Enabled when: react, react-router:6.4
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/react-router-loader-parallel-fetch. 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

export const loader = async () => {
  const project = await getProject();
  const activity = await getActivity();
  return { project, activity };
};

Corrected pattern

export const loader = async () => {
  const [project, activity] = await Promise.all([
    getProject(),
    getActivity(),
  ]);
  return { project, activity };
};

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/react-router-loader-parallel-fetch diagnostic in the current repository. Required change: - Start independent loader work together with Promise.all to avoid adding serial latency to navigation.

Reference transformation:Before:

export const loader = async () => {
  const project = await getProject();
  const activity = await getActivity();
  return { project, activity };
};

After:

export const loader = async () => {
  const [project, activity] = await Promise.all([
    getProject(),
    getActivity(),
  ]);
  return { project, activity };
};

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. - Preserve resource ownership and cleanup. Do not move work into a hotter render or frame path. - 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, react-router:6.4. 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 Performance rules from the rules reference:

react-doctor/react-router-prefer-route-lazy: React.lazy creates a route-module waterfall
react-doctor/redux-useselector-inline-derivation: Select the raw slice in useSelector and derive with useMemo, or hoist into a memoised createSelector from reselect.
react-doctor/redux-useselector-returns-new-collection: useSelector that returns a fresh object/array literal re-renders on every action; return a primitive, split into multiple useSelector calls, or pass shallowEqual.
react-doctor/rendering-animate-svg-wrapper: Wrap the SVG: `<motion.div animate={...}><svg>...</svg></motion.div>`
react-doctor/rendering-hoist-jsx: Move the static JSX to module scope: `const ICON = <svg>...</svg>` outside the component so it isn't recreated each render

react-doctor/react-router-loader-parallel-fetch