no-unknown-property

Keywords: React, JSX, props, HTML attributes, className, ESLint rule, DOM, LLM-optimized

Prevent unknown DOM properties in JSX. This rule is part of eslint-plugin-react-features.

Quick Summary

Rule Details

React uses camelCase for DOM attributes and has some renamed attributes (e.g., className instead of class).

Common Corrections

Examples

❌ Incorrect

<div class="container">Content</div>
<label for="input">Label</label>
<input tabindex="1" readonly />
<table cellpadding="5" cellspacing="0"></table>

✅ Correct

<div className="container">Content</div>
<label htmlFor="input">Label</label>
<input tabIndex={1} readOnly />
<table cellPadding={5} cellSpacing={0}></table>

Configuration Examples

Basic Usage

{
  rules: {
    'react-features/no-unknown-property': 'error'
  }
}

Related Rules

• no-invalid-html-attribute - Validate attribute values

Further Reading

• DOM Elements - React docs
• JSX Differences - HTML vs JSX

Known False Negatives

The following patterns are not detected due to static analysis limitations:

Dynamic Variable References

Why: Static analysis cannot trace values stored in variables or passed through function parameters.

// ❌ NOT DETECTED - Prop from variable
const propValue = computedValue;
<Component prop={propValue} /> // Computation not analyzed

Mitigation: Implement runtime validation and review code manually. Consider using TypeScript branded types for validated inputs.

Wrapped or Aliased Functions

Why: Custom wrapper functions or aliased methods are not recognized by the rule.

// ❌ NOT DETECTED - Custom wrapper
function myWrapper(data) {
  return internalApi(data); // Wrapper not analyzed
}
myWrapper(unsafeInput);

Mitigation: Apply this rule's principles to wrapper function implementations. Avoid aliasing security-sensitive functions.

Imported Values

Why: When values come from imports, the rule cannot analyze their origin or construction.

// ❌ NOT DETECTED - Value from import
import { getValue } from './helpers';
processValue(getValue()); // Cross-file not tracked

Mitigation: Ensure imported values follow the same constraints. Use TypeScript for type safety.