@cerios/openapi-core

Core utilities for parsing and processing OpenAPI specifications. This package provides the shared foundation for OpenAPI code generators.

Installation

npm install @cerios/openapi-core

Features

• 🔍 OpenAPI Parsing - Parse OpenAPI 3.0/3.1 YAML and JSON specifications
• 🔗 Reference Resolution - Resolve $ref references throughout the spec
• 🏷️ Operation Filtering - Filter operations by tags, paths, and methods
• 🛠️ Utility Functions - Common utilities for schema processing
• 📦 Batch Execution - Parallel and sequential execution of generators
• 🧪 Test Fixtures - Shared OpenAPI fixtures for testing

Usage

import {
	shouldIncludeOperation,
	toPascalCase,
	toCamelCase,
	resolveRefName,
	LRUCache,
	loadOpenAPISpec,
} from "@cerios/openapi-core";

// Load and parse an OpenAPI spec
const spec = await loadOpenAPISpec("openapi.yaml");

// Extract schema name from $ref
const schemaName = resolveRefName("#/components/schemas/User"); // "User"

// Filter operations
const include = shouldIncludeOperation(operation, path, method, {
	includeTags: ["users"],
	excludePaths: ["/internal/*"],
});

// Name utilities
const className = toPascalCase("user-profile"); // "UserProfile"
const methodName = toCamelCase("get-user-by-id"); // "getUserById"

API Reference

Types

• OpenAPISpec - OpenAPI specification structure
• OpenAPISchema - Schema definition structure
• OpenAPIParameter - Parameter definition
• OpenAPIRequestBody - Request body definition
• OpenAPIResponse - Response definition
• OperationFilters - Operation filtering options
• ExecutionMode - Parallel/sequential execution mode
• BaseGeneratorOptions - Base options for all generators

Spec Parsing

• loadOpenAPISpec() - Load and parse an OpenAPI spec file
• loadOpenAPISpecCached() - Load spec with LRU caching

Reference Resolution

• resolveRefName() - Extract name from $ref path
• resolveRequestBodyRef() - Resolve request body references
• resolveResponseRef() - Resolve response references
• mergeParameters() - Merge path and operation parameters

Operation Filtering

• shouldIncludeOperation() - Check if operation matches filters
• validateFilters() - Validate filter configuration
• createFilterStatistics() - Create filter statistics tracker
• formatFilterStatistics() - Format statistics for display

Name Utilities

• toPascalCase() - Convert string to PascalCase
• toCamelCase() - Convert string to camelCase
• resolveRefName() - Extract name from $ref path
• getOperationName() - Get operation name from operationId or path
• generateMethodNameFromPath() - Generate method name from path
• capitalize() - Capitalize first letter

Method Naming

• pathToPascalCase() - Convert path to PascalCase (e.g., /users/{userId} → UsersByUserId)
• generateHttpMethodName() - Generate method name from HTTP method + path
• extractPathParams() - Extract parameter names from path template
• sanitizeOperationId() - Sanitize operationId for TypeScript
• sanitizeParamName() - Sanitize parameter name for TypeScript

Schema Traversal

• extractSchemaRefs() - Extract all $ref names from schema tree
• expandTransitiveReferences() - Expand to include transitively referenced schemas
• detectCircularReferences() - Detect circular reference chains
• topologicalSortSchemas() - Sort schemas by dependencies
• analyzeSchemaUsage() - Analyze request/response context usage
• classifyEnumType() - Classify enum values as string/number/boolean/mixed

Header Filters

• shouldIgnoreHeader() - Check if header matches ignore patterns
• filterHeaders() - Filter headers excluding ignored ones
• validateIgnorePatterns() - Validate and warn about unmatched patterns

Pattern Utilities

• stripPrefix() - Strip prefix from schema names
• stripSuffix() - Strip suffix from strings
• stripAffixes() - Strip both prefix and suffix
• stripPathPrefix() - Strip prefix from paths (supports glob)
• isGlobPattern() - Check if string is a glob pattern

String Utilities

• escapeJSDoc() - Escape JSDoc content
• escapeDescription() - Escape description text
• escapePattern() - Escape regex pattern
• getPrimaryType() - Get primary type from schema
• hasMultipleTypes() - Check if schema has multiple types
• isNullable() - Check if schema is nullable

Content Type Utilities

• getResponseParseMethod() - Determine response parsing method (json, text, blob, etc.)

Config Loader

• createConfigLoader() - Factory for type-safe config loaders with cosmiconfig + Zod validation
• mergeCliWithConfig() - Merge CLI options with config values (CLI takes precedence)

CLI Utilities

• findSpecFiles() - Find OpenAPI spec files in directory
• getRandomCeriosMessage() - Get random CLI greeting message

Classes

• LRUCache - Least Recently Used cache implementation
• GeneratorError - Base error class for generators
• SpecValidationError - OpenAPI spec validation errors
• FileOperationError - File I/O errors
• ConfigValidationError - Configuration errors
• CircularReferenceError - Circular reference detection errors
• CliOptionsError - CLI options validation errors
• SchemaGenerationError - Schema generation errors

Batch Execution

• executeBatch() - Execute multiple generators
• getBatchExitCode() - Calculate exit code from results
• Generator - Interface for generator implementations

License

MIT