Swc Config Validator

Validate SWC config files (.swcrc, package.json#swc) for parser settings, transform conflicts, module type issues, and best practices. Use when validating SWC transpiler configs, auditing Next.js/Turbopack build setups, or linting swc config files.

Validate .swcrc and package.json#swc for parser errors, invalid targets, transform conflicts, module type issues, minification problems, and best practices. Supports text, JSON, and summary output formats with CI-friendly exit codes.

Commands

bash

# Full validation (all 22+ rules)
python3 scripts/swc_config_validator.py validate .swcrc

# Quick syntax/structure check only
python3 scripts/swc_config_validator.py check .swcrc

# Explain config in human-readable form
python3 scripts/swc_config_validator.py explain .swcrc

# Suggest improvements
python3 scripts/swc_config_validator.py suggest .swcrc

# JSON output (CI-friendly)
python3 scripts/swc_config_validator.py validate .swcrc --format json

# Summary only (pass/fail + counts)
python3 scripts/swc_config_validator.py validate .swcrc --format summary

# Strict mode (warnings become errors)
python3 scripts/swc_config_validator.py validate .swcrc --strict

# Validate from package.json#swc
python3 scripts/swc_config_validator.py validate package.json

Rules (22+)

#	Category	Severity	Rule
S1	Structure	Error	File not found or unreadable
S2	Structure	Error	Empty config
S3	Structure	Error	Invalid JSON syntax
S4	Structure	Warning	Unknown top-level keys
S5	Structure	Warning	Missing jsc key (most configs need it)
J1	JSC Config	Error	Invalid parser syntax (must be ecmascript or typescript)
J2	JSC Config	Warning	JSX enabled in parser without React transform
J3	JSC Config	Warning	Deprecated loose mode in jsc.transform
J4	JSC Config	Warning	Missing target (no compilation target specified)
J5	JSC Config	Error	Invalid target value (not es3/es5/es2015-es2024/esnext)
M1	Modules	Error	Unknown module type
M2	Modules	Warning	isModule: false with ESM module type
M3	Modules	Warning	CommonJS module with ESM-only parser features
T1	Transform	Error	React transform without parser.jsx enabled
T2	Transform	Warning	Legacy decorators without decoratorsBeforeExport
T3	Transform	Warning	Conflicting useDefineForClassFields with TypeScript
T4	Transform	Warning	Deprecated constModules in jsc.experimental
N1	Minification	Warning	Minification enabled with compress: false
N2	Minification	Warning	Mangle enabled without compress
N3	Minification	Warning	Drop console in development config
B1	Best Practices	Warning	sourceMaps not configured
B2	Best Practices	Info	No env config for different environments

Output Formats

• text (default): Human-readable with severity icons
• json: Machine-parseable JSON array of findings
• summary: Pass/fail with error/warning counts

Exit Codes

• 0: No errors (warnings/info only or clean)
• 1: One or more errors found
• 2: File not found or invalid input

Requirements

• Python 3.8+
• No external dependencies (pure stdlib)

Supported Targets

es3, es5, es2015 through es2024, esnext

Supported Module Types

es6, commonjs, umd, amd, nodenext, systemjs

Valid Top-Level Keys

$schema, jsc, module, minify, env, isModule, sourceMaps, inlineSourcesContent, emitSourceMapColumns, inputSourceMap, test, exclude, filename