type-explorer

A powerful runtime type analysis and schema generation utility for TypeScript/JavaScript that provides deep structural analysis of values and automatic schema generation for popular validation libraries.

Key Features

• Deep Type Analysis

  • Comprehensive inspection of complex data structures
  • Circular reference detection
  • Support for all JavaScript built-in types
  • Custom type handler registration
  • Configurable analysis depth

• Schema Generation

  • Multi-library support (Zod, Joi, Yup, OpenAPI)
  • Type-safe schema generation
  • Automatic type inference
  • Support for complex nested structures

• Developer Experience

  • TypeScript-first design
  • Extensive configuration options
  • Predefined analysis presets
  • Detailed type information

Installation

# Using bun
bun add type-explorer

# Using npm
npm install type-explorer

# Using yarn
yarn add type-explorer

# Using pnpm
pnpm add type-explorer

Quick Start

import { TypeAnalyzer } from "type-explorer";

// Initialize analyzer
const analyzer = new TypeAnalyzer();

// Analyze data structure
const result = analyzer.analyze({
  user: {
    id: 1,
    name: "John Doe",
    roles: ["admin", "user"],
    lastLogin: new Date(),
  },
});

// Generate schema (e.g., using Zod)
import { ZodSchemaAdapter } from "type-explorer";
const zodAdapter = new ZodSchemaAdapter();
const schema = zodAdapter.generateSchemaFromData(data);

Core Concepts

Type Analysis

The TypeAnalyzer provides detailed information about your data structures:

const analysis = analyzer.analyze({
  name: "John",
  age: 30,
  hobbies: ["reading", "coding"],
  metadata: {
    lastLogin: new Date(),
    preferences: { theme: "dark" },
  },
});

Analysis Configuration

Customize the analysis depth and detail level:

const analyzer = new TypeAnalyzer({
  maxDepth: 10, // Maximum recursion depth
  includeMethods: true, // Include function analysis
  includeGettersSetters: true, // Include accessor properties
  includePrototype: true, // Include prototype chain
  includePrivateProps: false, // Exclude private properties
});

Preset Configurations

import { CONFIG_PRESETS } from "type-explorer";

// Quick surface-level analysis
const minimalAnalyzer = new TypeAnalyzer(CONFIG_PRESETS.MINIMAL);

// Balanced depth and detail (default)
const standardAnalyzer = new TypeAnalyzer(CONFIG_PRESETS.STANDARD);

// Deep inspection including private properties
const detailedAnalyzer = new TypeAnalyzer(CONFIG_PRESETS.DETAILED);

Schema Generation

Zod Schemas

import { ZodSchemaAdapter } from "type-explorer";
import { z } from "zod";

const zodAdapter = new ZodSchemaAdapter();
const schemaString = zodAdapter.generateSchemaFromData(data);
const schema = new Function("z", `return ${schemaString}`)(z);

console.log(schema.parse(data));

Supported types:

• Primitives (string, number, boolean, null, undefined)
• Complex types (object, array, Date, enum, union)
• Modifiers (optional, nullable)

Joi Schemas

import { JoiSchemaAdapter } from "type-explorer";
import * as Joi from "joi";

const joiAdapter = new JoiSchemaAdapter();
const schemaString = joiAdapter.generateSchemaFromData(data);
const schema = new Function("Joi", `return ${schemaString}`)(Joi);

console.log(schema.validate(data));

Supported types:

• Primitives (string, number, boolean, null, undefined)
• Complex types (object, array, Date)
• Validation features (valid(), alternatives().try(), allow(null))

Yup Schemas

import { YupSchemaAdapter } from "type-explorer";
import * as yup from "yup";

const yupAdapter = new YupSchemaAdapter();
const schemaString = yupAdapter.generateSchemaFromData(data);
const schema = new Function("yup", `return ${schemaString}`)(yup);

console.log(schema.validateSync(data));

Supported types:

• Primitives (string, number, boolean, null, undefined)
• Complex types (object, array, Date)
• Validation features (oneOf(), nullable(), optional())

OpenAPI Schemas

import { OpenAPISchemaAdapter } from "type-explorer";

const openAPIAdapter = new OpenAPISchemaAdapter();
const schemaString = openAPIAdapter.generateSchemaFromData(data);
const schema = JSON.parse(schemaString);
console.log(schema);

Supported features:

• OpenAPI 3.0 specification
• All standard JSON Schema types
• Nullable properties
• References ($ref)
• Property descriptions

Advanced Usage

Custom Type Handlers

Register custom type handlers for specialized classes:

analyzer.registerCustomType("MyClass", (value, context) => ({
  type: "MyClass",
  customProperty: value.someProperty,
  path: [...context.path],
}));

Error Handling

try {
  const schema = adapter.generateSchemaFromData(data);
  const validationResult = schema.safeParse(testData);

  if (!validationResult.success) {
    console.error("Validation errors:", validationResult.error);
  }
} catch (error) {
  console.error("Schema generation error:", error);
}

Type Analysis Results

The analyzer provides detailed type information:

interface AnalysisResult {
  type: string; // Type identifier
  path: (string | number)[]; // Property path
  properties?: Record<string, AnalysisResult>; // For objects
  elementTypes?: Array<{
    // For arrays
    type: AnalysisResult;
    frequency: number;
    count: number;
    indices: number[];
  }>;
  // ... additional type-specific properties
}

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Links

• GitHub Repository
• Issue Tracker
• Documentation