packages/mcp/src/schema-utils.ts - main - githubmirror/Front-End-Checklist

packages/mcp/src/schema-utils.ts
88 строк2 KB
David Dias
chore: new v2 version
30 май 2026, 00:54
30 май 2026, 00:547c05904
import * as z from 'zod'

interface JsonLikeSchema {
  type?: string | string[]
  enum?: readonly string[]
  properties?: Record<string, JsonLikeSchema>
  items?: JsonLikeSchema
  required?: string[]
  [key: string]: unknown
}

/**
 * Mark a derived Zod schema nullable when JSON Schema includes `null`.
 *
 * @param schema - Base Zod schema.
 * @param type - Raw JSON Schema type field.
 * @returns Nullable or original schema depending on the input type.
 */
function applyNullable(schema: z.ZodTypeAny, type: JsonLikeSchema['type']): z.ZodTypeAny {
  if (!Array.isArray(type) || !type.includes('null')) {
    return schema
  }

  return schema.nullable()
}

/**
 * Convert a JSON Schema object shape into a Zod object schema.
 *
 * @param schema - JSON-like object schema.
 * @returns Zod object schema with optional fields handled from `required`.
 */
function buildObjectSchema(schema: JsonLikeSchema): z.ZodTypeAny {
  const required = new Set(schema.required || [])
  const shape = Object.fromEntries(
    Object.entries(schema.properties || {}).map(([key, value]) => {
      const propertySchema = required.has(key)
        ? jsonSchemaToZod(value)
        : jsonSchemaToZod(value).optional()
      return [key, propertySchema]
    })
  )

  return z.object(shape).catchall(z.any())
}

/**
 * Convert a small subset of JSON Schema into a matching Zod schema.
 *
 * @param schema - JSON-like schema definition.
 * @returns Zod schema used by MCP tool registration.
 */
export function jsonSchemaToZod(schema: JsonLikeSchema | undefined): z.ZodTypeAny {
  if (!schema) {
    return z.any()
  }

  if (schema.enum && schema.enum.length > 0) {
    const values = [...schema.enum]
    const enumSchema =
      values.length === 1
        ? z.literal(values[0])
        : z.enum([values[0], ...values.slice(1)] as [string, ...string[]])

    return applyNullable(enumSchema, schema.type)
  }

  const type = Array.isArray(schema.type)
    ? schema.type.filter(value => value !== 'null')[0]
    : schema.type

  switch (type) {
    case 'string':
      return applyNullable(z.string(), schema.type)
    case 'number':
      return applyNullable(z.number(), schema.type)
    case 'boolean':
      return applyNullable(z.boolean(), schema.type)
    case 'array': {
      const itemSchema = jsonSchemaToZod(schema.items)
      return applyNullable(z.array(itemSchema), schema.type)
    }
    default: {
      const objectSchema = buildObjectSchema(schema)
      return applyNullable(objectSchema, schema.type)
    }
  }
}