code-quality

# Code Quality Measure, enforce, and improve code quality across languages. ## Linting ### JavaScript/TypeScript ```bash # ESLint — find issues npx eslint src/ --format json | jq '[.[] | select(.errorCount > 0 or .warningCount > 0) | {file: .filePath, errors: .errorCount, warnings: .warningCount}]' # Auto-fix npx eslint src/ --fix # Specific rules only npx eslint src/ --rule '{"no-unused-vars": "error"}' ``` ### Python ```bash # Ruff — fast linter + formatter ruff check src/ ruff check src/ --fix # Type checking mypy src/ --ignore-missing-imports # Both together ruff check src/ && mypy src/ ``` ### Go ```bash # golangci-lint — meta linter golangci-lint run ./... # With specific linters golangci-lint run --enable gosec,govet,errcheck,staticcheck ./... # JSON output golangci-lint run --out-format json ./... | jq '.Issues[] | {file: .Pos.Filename, line: .Pos.Line, linter: .FromLinter, text: .Text}' ``` ### Rust ```bash # Clippy — Rust linter cargo clippy -- -W clippy::all # Treat warnings as errors cargo clippy -- -D warnings # With suggestions cargo clippy --fix ``` ## Formatting ```bash # Prettier (JS/TS/CSS/JSON/MD) npx prettier --check "src/**/*.{ts,tsx,js,jsx}" npx prettier --write "src/**/*.{ts,tsx,js,jsx}" # Ruff format (Python) ruff format src/ ruff format --check src/ # gofmt (Go) gofmt -l . gofmt -w . # rustfmt (Rust) cargo fmt --check cargo fmt ``` ## Code Coverage ```bash # Jest (JS/TS) npx jest --coverage --json | jq '{lines: .coverageMap | to_entries | map(.value.s | to_entries | map(.value) | {total: length, covered: map(select(. > 0)) | length}) | {total: map(.total) | add, covered: map(.covered) | add} | {pct: (100 * .covered / .total | floor)}}' # Simpler: just run and read summary npx jest --coverage 2>&1 | tail -10 # pytest (Python) pytest --cov=src --cov-report=term-missing # Go go test -coverprofile=coverage.out ./... go tool cover -func=coverage.out | tail -1 # Rust cargo tarpaulin --out stdout ``` ## Complexity Metrics ```bash # Python — cyclomatic complexity radon cc src/ -a -s -nb # Python — maintainability index radon mi src/ -s -nb # JavaScript/TypeScript — complexity via ESLint npx eslint src/ --rule '{"complexity": ["warn", 10]}' --format json | jq '[.[] | .messages[] | select(.ruleId == "complexity") | {file: input.filePath, line: .line, message: .message}]' ``` ## Tech Debt Indicators Look for these patterns: ```bash # TODO/FIXME/HACK comments grep -rn "TODO\|FIXME\|HACK\|XXX\|TEMP" src/ --include="*.ts" --include="*.py" --include="*.go" | wc -l # List them grep -rn "TODO\|FIXME\|HACK" src/ --include="*.ts" --include="*.py" # Long files (>300 lines) find src/ -name "*.ts" -o -name "*.py" | xargs wc -l | sort -rn | head -20 # Duplicate code detection (Python) # Install: pip install pylint pylint --disable=all --enable=duplicate-code src/ ``` ## Notes - Run linting on changed files only in CI for speed: `eslint $(git diff --name-only --diff-filter=ACMR HEAD~1 | grep -E '\.(ts|tsx|js)$')`. - Coverage percentage alone is misleading — 80% with no edge case tests is worse than 60% with thorough tests. - Fix linting errors incrementally. Don't dump 500 fixes into one commit. - Complexity > 10 is a code smell. > 20 needs refactoring.