@maastrich/zod-resolve

Type-safe Zod sub-schema resolver using path notation with support for arrays, tuples, and unions.

Installation

npm install @maastrich/zod-resolve
# or
pnpm add @maastrich/zod-resolve
# or
yarn add @maastrich/zod-resolve

Quick Start

import { z } from "zod";
import { resolve } from "@maastrich/zod-resolve";

const userSchema = z.object({
  name: z.string(),
  profile: z.object({
    age: z.number(),
    email: z.string().email(),
  }),
  posts: z.array(
    z.object({
      title: z.string(),
      tags: z.array(z.string()),
    })
  ),
});

// Resolve nested schemas using path notation
const nameSchema = resolve(userSchema, "name"); // ZodString
const ageSchema = resolve(userSchema, "profile.age"); // ZodNumber
const postSchema = resolve(userSchema, "posts[]"); // ZodObject
const tagSchema = resolve(userSchema, "posts[].tags[]"); // ZodString

// Use resolved schemas for validation
nameSchema.parse("John Doe"); // ✓
ageSchema.parse(25); // ✓
tagSchema.parse("typescript"); // ✓

Features

• Type-safe path strings - Full TypeScript autocomplete and validation
• Dot notation - Navigate nested objects: user.profile.name
• Array access - Access array elements: items[], users[].posts[]
• Tuple indexing - Access tuple elements by index: coordinates[0]
• Union support - Access fields from all union branches
• Smart unwrapping - Automatic unwrapping of optional/nullable wrappers for traversal

Core API

resolve(schema, path)

Resolves a sub-schema at the given path.

import { resolve } from "@maastrich/zod-resolve";

const schema = z.object({
  user: z.object({ name: z.string() }),
});

const nameSchema = resolve(schema, "user.name"); // ZodString

Full API Documentation →

flatten(schema)

Flattens a schema into a record of all accessible paths.

import { flatten } from "@maastrich/zod-resolve";

const schema = z.object({
  name: z.string(),
  items: z.array(z.number()),
});

const flat = flatten(schema);
// {
//   name: ZodString,
//   items: ZodArray<ZodNumber>,
//   'items[]': ZodNumber
// }

Path Syntax

Pattern	Example	Description
Property access	user.name	Navigate nested objects using dots
Array elements	items[]	Access array element schema
Tuple indices	coords[0]	Access tuple element by index
Combined	users[].posts[].tags[]	Navigate complex nested structures

Complete Path Syntax Guide →

Examples

Basic Usage

const schema = z.object({
  id: z.string(),
  metadata: z.object({
    created: z.string(),
    updated: z.string(),
  }),
});

resolve(schema, "id"); // ZodString
resolve(schema, "metadata.created"); // ZodString

Arrays

const schema = z.object({
  users: z.array(
    z.object({
      name: z.string(),
      contacts: z.array(z.string()),
    })
  ),
});

resolve(schema, "users[]"); // ZodObject
resolve(schema, "users[].name"); // ZodString
resolve(schema, "users[].contacts[]"); // ZodString

Tuples

const schema = z.object({
  coordinates: z.tuple([
    z.number(), // latitude
    z.number(), // longitude
  ]),
});

resolve(schema, "coordinates[0]"); // ZodNumber (latitude)
resolve(schema, "coordinates[1]"); // ZodNumber (longitude)

Unions

const schema = z.union([
  z.object({ type: z.literal("car"), doors: z.number() }),
  z.object({ type: z.literal("bike"), gears: z.number() }),
]);

resolve(schema, "type"); // ZodUnion<[ZodLiteral<'car'>, ZodLiteral<'bike'>]>
resolve(schema, "doors"); // ZodNumber
resolve(schema, "gears"); // ZodNumber

More Examples →

Use Cases

• Form validation - Validate individual form fields dynamically
• API validation - Resolve schemas for nested API response fields
• Type-safe builders - Create type-safe path-based utilities
• Schema introspection - Analyze and traverse schema structures
• Dynamic validation - Build flexible validation logic

Documentation

• API Reference - Complete API documentation
• Path Syntax Guide - Detailed path notation reference
• Examples - Practical usage examples

Requirements

• zod ^3.0.0
• TypeScript 5.0+

License

MIT © Mathis Pinsault