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# Rule Management
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Oxlint provides a hierarchical rule management system with categories, individual rule configuration, and flexible severity controls. Rules can be configured through command-line options or configuration files with fine-grained control over scope and application.
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## Rule Categories
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Oxlint organizes rules into logical categories that can be enabled or disabled as groups:
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### Correctness
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```bash { .api }
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oxlint -D correctness  # Deny (error level)
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oxlint -W correctness  # Warn level
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oxlint -A correctness  # Allow (suppress)
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```
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Code that is outright wrong or useless. Enabled by default at error level.
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**Examples:** `no-debugger`, `no-unreachable`, `no-duplicate-keys`
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### Suspicious
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```bash { .api }
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oxlint -D suspicious
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oxlint -W suspicious
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oxlint -A suspicious
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```
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Code that is most likely wrong or problematic but may have legitimate uses.
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**Examples:** `no-empty`, `no-implicit-coercion`, `no-unused-vars`
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### Pedantic
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```bash { .api }
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oxlint -D pedantic
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oxlint -W pedantic
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oxlint -A pedantic
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```
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Strict rules that enforce best practices but may have occasional false positives.
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**Examples:** `prefer-const`, `no-var`, `eqeqeq`
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### Style
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```bash { .api }
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oxlint -D style
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oxlint -W style
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oxlint -A style
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```
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Code style and formatting rules for consistent code appearance.
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**Examples:** `semi`, `quotes`, `indent`, `comma-dangle`
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### Nursery
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```bash { .api }
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oxlint -D nursery
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oxlint -W nursery
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oxlint -A nursery
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```
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New rules under development that may change behavior or have limited testing.
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### Restriction
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```bash { .api }
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oxlint -D restriction
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oxlint -W restriction
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oxlint -A restriction
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```
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Rules that prevent the use of specific language features or patterns.
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**Examples:** `no-eval`, `no-with`, `no-implicit-globals`
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### All Categories
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```bash { .api }
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oxlint -A all  # Allow all rules
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oxlint -D all  # Deny all rules (except nursery)
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```
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Applies to all categories except nursery. Does not automatically enable plugins.
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## Rule Severity Levels
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### Command Line Severity Control
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```bash { .api }
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# Allow (suppress) - rules produce no output
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oxlint --allow RULE_NAME
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oxlint -A RULE_NAME
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# Warn - rules produce warnings (exit code 0 unless --deny-warnings)
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oxlint --warn RULE_NAME
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oxlint -W RULE_NAME
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# Deny (error) - rules produce errors (exit code 1)
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oxlint --deny RULE_NAME
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oxlint -D RULE_NAME
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```
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### Configuration File Severity
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```json { .api }
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{
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  "rules": {
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    "rule-name": "off",     // 0 - disable rule
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    "rule-name": "warn",    // 1 - warning level
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    "rule-name": "error"    // 2 - error level
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  }
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}
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```
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## Individual Rule Configuration
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### Basic Rule Configuration
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```json { .api }
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{
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  "rules": {
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    "no-debugger": "error",
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    "no-console": "warn",
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    "no-unused-vars": "off",
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    "eqeqeq": "error",
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    "prefer-const": "warn"
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  }
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}
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```
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### Rule Configuration with Options
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```json { .api }
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{
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  "rules": {
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    "prefer-const": ["error", {
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      "destructuring": "any",
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      "ignoreReadBeforeAssign": false
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    }],
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    "no-unused-vars": ["warn", {
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      "vars": "all",
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      "args": "after-used",
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      "ignoreRestSiblings": true
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    }],
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    "quotes": ["error", "single", {
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      "avoidEscape": true,
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      "allowTemplateLiterals": false
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    }]
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  }
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}
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```
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## Command Line Rule Management
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### Layered Rule Configuration
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Rules are applied in order from left to right, allowing fine-grained control:
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```bash
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# Start with all rules allowed, then deny specific categories
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oxlint -A all -D correctness -D suspicious src/
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# Allow a category but deny specific rules
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oxlint -A pedantic -D prefer-const -D no-var src/
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# Mix of category and individual rule controls
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oxlint -D suspicious --allow no-debugger -W no-console src/
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```
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### Rule Precedence
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Command-line options override configuration file settings:
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```bash
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# Override config file rules
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oxlint -c .oxlintrc.json -A no-debugger -D prefer-const src/
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```
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## Advanced Rule Management
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### File-Specific Rule Overrides
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```json { .api }
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{
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  "rules": {
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    "no-console": "error"
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  },
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  "overrides": [
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    {
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      "files": ["**/*.test.js", "**/*.spec.js"],
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      "rules": {
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        "no-console": "off"
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      }
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    },
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    {
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      "files": ["scripts/**/*.js"],
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      "rules": {
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        "no-console": "warn",
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        "no-process-exit": "off"
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      }
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    }
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  ]
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}
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```
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### Plugin-Specific Rules
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```json { .api }
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{
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  "plugins": ["typescript", "react"],
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  "rules": {
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    // TypeScript rules
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    "@typescript-eslint/no-unused-vars": "error",
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    "@typescript-eslint/explicit-function-return-type": "warn",
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    // React rules
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    "react/jsx-uses-react": "error",
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    "react/jsx-uses-vars": "error",
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    // Disable conflicting core rules when using TypeScript
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    "no-unused-vars": "off"
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  }
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}
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```
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### Category-Level Configuration
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```json { .api }
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{
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  "categories": {
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    "correctness": "error",
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    "suspicious": "warn",
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    "pedantic": "off",
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    "style": "warn"
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  },
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  "rules": {
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    // Override specific rules within categories
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    "no-debugger": "warn",  // Override correctness default
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    "prefer-const": "error" // Override pedantic default
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  }
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}
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```
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## Rule Discovery and Information
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### List Available Rules
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```bash { .api }
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oxlint --rules
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```
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Displays all available rules organized by plugin and category.
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### Rule Documentation
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Rules follow standard naming conventions:
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- Core rules: `rule-name`
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- Plugin rules: `plugin-name/rule-name`
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- TypeScript rules: `@typescript-eslint/rule-name`
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## Warning and Error Handling
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### Warning Thresholds
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```bash { .api }
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# Set maximum number of warnings before exit code 1
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oxlint --max-warnings 10 src/
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# Treat any warning as error
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oxlint --deny-warnings src/
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# Suppress warnings, show errors only
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oxlint --quiet src/
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```
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### Inline Directive Reporting
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```bash { .api }
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# Report unused eslint-disable directives
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oxlint --report-unused-disable-directives src/
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# Report with specific severity
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oxlint --report-unused-disable-directives-severity error src/
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```
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## Common Rule Configuration Patterns
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### Strict Configuration
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```json
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{
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  "categories": {
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    "correctness": "error",
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    "suspicious": "error",
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    "pedantic": "error"
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  },
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  "rules": {
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    "no-debugger": "error",
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    "no-console": "error",
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    "eqeqeq": "error",
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    "prefer-const": "error"
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  }
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}
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```
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### Gradual Adoption
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```json
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{
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  "categories": {
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    "correctness": "error",
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    "suspicious": "warn",
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    "pedantic": "off"
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  },
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  "rules": {
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    // Gradually enable pedantic rules
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    "prefer-const": "warn",
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    "no-var": "warn"
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  }
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}
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```
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### Framework-Specific Rules
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```json
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  "plugins": ["react", "typescript"],
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  "overrides": [
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    {
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      "files": ["**/*.tsx", "**/*.jsx"],
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      "rules": {
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        "react/jsx-uses-react": "error",
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        "react/jsx-key": "error",
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        "react/no-unused-state": "warn"
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      }
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    },
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    {
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      "files": ["**/*.ts", "**/*.tsx"],
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      "rules": {
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        "@typescript-eslint/no-unused-vars": "error",
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        "@typescript-eslint/no-explicit-any": "warn",
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        "no-unused-vars": "off"
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      }
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    }
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  ]
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}
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```