# `react-doctor/motion-value-subscription-in-render`

Motion value subscription is created during render

- **Category:** Bugs
- **Severity:** error
- **Source:** oxlint-plugin-react-doctor
- **Framework:** global
- **Enabled when:** always

## Validate the diagnostic

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

Confirm the reported code matches `react-doctor/motion-value-subscription-in-render`. 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

```tsx
import { useMotionValue } from "motion/react";

const Slider = () => {
  const motionValue = useMotionValue(0);
  motionValue.on("change", updateLabel);
  return <output>{motionValue.get()}</output>;
};
```

### Corrected pattern

```tsx
import {
  useMotionValue,
  useMotionValueEvent,
} from "motion/react";

const Slider = () => {
  const motionValue = useMotionValue(0);
  useMotionValueEvent(motionValue, "change", updateLabel);
  return <output>{motionValue.get()}</output>;
};
```

## 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.

````text
Fix every confirmed `react-doctor/motion-value-subscription-in-render` diagnostic in the current repository.

Required change:
- Subscribe with useMotionValueEvent, or create the subscription in an effect and return its cleanup function.

Reference transformation:

Before:
```tsx
import { useMotionValue } from "motion/react";

const Slider = () => {
  const motionValue = useMotionValue(0);
  motionValue.on("change", updateLabel);
  return <output>{motionValue.get()}</output>;
};
```

After:
```tsx
import {
  useMotionValue,
  useMotionValueEvent,
} from "motion/react";

const Slider = () => {
  const motionValue = useMotionValue(0);
  useMotionValueEvent(motionValue, "change", updateLabel);
  return <output>{motionValue.get()}</output>;
};
```

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.
````