# `react-doctor/styled-components-duplicate-css-property-in-block`

Duplicate CSS property in styled block

- **Category:** Maintainability
- **Severity:** warn
- **Source:** oxlint-plugin-react-doctor
- **Framework:** global
- **Enabled when:** styled-components

## Validate the diagnostic

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

Confirm the reported code matches `react-doctor/styled-components-duplicate-css-property-in-block`. 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 styled from "styled-components";
const Button = styled.button`
  padding: ${(props) => props.compact ? "4px" : "8px"};
  padding: ${(props) => props.large ? "16px" : "8px"};
`;
```

### Corrected pattern

```tsx
import styled from "styled-components";
const Button = styled.button`
  padding: ${(props) => {
    if (props.compact) return "4px";
    if (props.large) return "16px";
    return "8px";
  }};
`;
```

## 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/styled-components-duplicate-css-property-in-block` diagnostic in the current repository.

Required change:
- Keep one declaration per CSS property in each styled block. Compute conditional values in that declaration.

Reference transformation:

Before:
```tsx
import styled from "styled-components";
const Button = styled.button`
  padding: ${(props) => props.compact ? "4px" : "8px"};
  padding: ${(props) => props.large ? "16px" : "8px"};
`;
```

After:
```tsx
import styled from "styled-components";
const Button = styled.button`
  padding: ${(props) => {
    if (props.compact) return "4px";
    if (props.large) return "16px";
    return "8px";
  }};
`;
```

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.
- Use existing brand assets, product facts, content, and design tokens.
- Do not invent claims, customer data, typefaces, or artwork.
- 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: `styled-components`.

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.
````