PaginatedResult

Overview

PaginatedResult wraps query results with pagination metadata. It provides a consistent structure for paginated data and handles deep serialization of entities and value objects.

const result = await userRepository.find(criteria);

// Access data and metadata
result.data; // User[] - the actual entities
result.meta.page; // 1
result.meta.limit; // 20
result.meta.total; // 150
result.meta.totalPages; // 8
result.meta.hasNext; // true
result.meta.hasPrevious; // false

Creating PaginatedResult

From Repository

Most commonly, you’ll get PaginatedResult from repository methods:

const criteria = Criteria.create<User>()
  .whereEquals("status", "active")
  .orderByDesc("createdAt")
  .paginate(1, 20);

const result = await userRepository.find(criteria);
// PaginatedResult<User>

Manual Creation

Create a PaginatedResult directly:

import { PaginatedResult } from "@woltz/rich-domain";

const users: User[] = [...]; // Your data
const pagination = { page: 1, limit: 20, offset: 0 };
const total = 150;

const result = PaginatedResult.create(users, pagination, total);

From Array (Testing/In-Memory)

Apply criteria to an in-memory array:

const allUsers: User[] = [...]; // All users in memory

const criteria = Criteria.create<User>()
  .whereEquals("status", "active")
  .orderByDesc("createdAt")
  .paginate(1, 20);

const result = PaginatedResult.fromArray(allUsers, criteria);
// Filters, orders, and paginates the array

fromArray() is useful for testing or when working with small datasets. For large datasets, always use database-level filtering.

Pagination Metadata

PaginationMeta Structure

interface PaginationMeta {
  page: number; // Current page (1-based)
  limit: number; // Items per page
  total: number; // Total matching records
  totalPages: number; // Total number of pages
  hasNext: boolean; // Has next page
  hasPrevious: boolean; // Has previous page
}

Accessing Metadata

const result = await userRepository.find(criteria);

console.log(result.meta);
// {
//   page: 1,
//   limit: 20,
//   total: 150,
//   totalPages: 8,
//   hasNext: true,
//   hasPrevious: false
// }

// Individual properties
result.meta.page; // 1
result.meta.limit; // 20
result.meta.total; // 150
result.meta.totalPages; // 8
result.meta.hasNext; // true
result.meta.hasPrevious; // false

Creating Metadata Manually

const pagination = { page: 2, limit: 10, offset: 10 };
const total = 45;

const meta = PaginatedResult.createMeta(pagination, total);
// {
//   page: 2,
//   limit: 10,
//   total: 45,
//   totalPages: 5,
//   hasNext: true,
//   hasPrevious: true
// }

Utility Properties

isEmpty

Check if result has no data:

const result = await userRepository.find(criteria);

if (result.isEmpty) {
  console.log("No users found");
}

hasMore

Check if there are more pages:

const result = await userRepository.find(criteria);

if (result.hasMore) {
  // Show "Load More" button
}

// Same as result.meta.hasNext

Transforming Results

map()

Transform each item in the result:

const users = await userRepository.find(criteria);

// Transform to DTOs
const userDtos = users.map((user) => ({
  id: user.id.value,
  displayName: `${user.firstName} ${user.lastName}`,
  email: user.email,
  avatarUrl: user.profile?.avatarUrl || "/default-avatar.png",
}));

// userDtos is PaginatedResult<UserDto>
// Metadata is preserved

Chaining map()

const result = await orderRepository.find(criteria);

const summaries = result
  .map((order) => ({
    id: order.id.value,
    total: order.total,
    itemCount: order.items.length,
    customer: order.customer.name,
  }))
  .map((summary) => ({
    ...summary,
    formattedTotal: `$${summary.total.toFixed(2)}`,
  }));

Serialization

toJSON()

Deep serialize all entities, value objects, and IDs:

const result = await userRepository.find(criteria);

const json = result.toJSON();
// {
//   data: [
//     {
//       id: "user-123",  // Id serialized to string
//       name: "John Doe",
//       email: "john@example.com",
//       address: {        // Value Object serialized
//         street: "123 Main St",
//         city: "New York"
//       },
//       posts: [          // Nested entities serialized
//         { id: "post-1", title: "Hello World" },
//         { id: "post-2", title: "Another Post" }
//       ]
//     },
//     // ... more users
//   ],
//   meta: {
//     page: 1,
//     limit: 20,
//     total: 150,
//     totalPages: 8,
//     hasNext: true,
//     hasPrevious: false
//   }
// }

What Gets Serialized

Type	Serialization
`Id`	String value (`id.value`)
`Entity`	Calls `toJson()`
`Aggregate`	Calls `toJson()`
`ValueObject`	Calls `toJson()`
`Date`	ISO string
`Array`	Maps items recursively
`Plain Object`	Serializes properties recursively
`Primitives`	As-is

Type Safety

The return type reflects serialization:

type PaginatedJsonResult<T> = {
  data: InferJsonResult<T>[]; // Serialized data
  meta: PaginationMeta;
};

// InferJsonResult transforms:
// - Entities → their toJson() return type
// - Other types → as-is

API Response Pattern

// Express.js
app.get("/users", async (req, res) => {
  const criteria = Criteria.fromQueryParams<User>(req.query);
  const result = await userRepository.find(criteria);

  // toJSON() for API response
  res.json(result.toJSON());
});

// Fastify
fastify.get("/users", async (request, reply) => {
  const criteria = Criteria.fromQueryParams<User>(request.query);
  const result = await userRepository.find(criteria);

  return result.toJSON();
});

Pagination UI Example

// Backend
const result = await userRepository.find(criteria);
const response = result.toJSON();

// Frontend - React example
function UserList({ data, meta }: PaginatedJsonResult<User>) {
  return (
    <div>
      {/* Data */}
      <ul>
        {data.map((user) => (
          <li key={user.id}>{user.name}</li>
        ))}
      </ul>

      {/* Pagination */}
      <div className="pagination">
        <button
          disabled={!meta.hasPrevious}
          onClick={() => goToPage(meta.page - 1)}
        >
          Previous
        </button>

        <span>
          Page {meta.page} of {meta.totalPages}
        </span>

        <button
          disabled={!meta.hasNext}
          onClick={() => goToPage(meta.page + 1)}
        >
          Next
        </button>
      </div>

      {/* Info */}
      <p>
        Showing {data.length} of {meta.total} users
      </p>
    </div>
  );
}

Complete Example

// Repository implementation
class UserRepository extends Repository<User> {
  async findActiveUsers(
    page: number,
    limit: number,
    search?: string
  ): Promise<PaginatedResult<User>> {
    let criteria = Criteria.create<User>()
      .whereEquals("status", "active")
      .whereNotNull("emailVerifiedAt")
      .orderByDesc("createdAt")
      .paginate(page, limit);

    if (search) {
      criteria = criteria.search(["name", "email"], search);
    }

    return this.find(criteria);
  }
}

// API endpoint
app.get("/users", async (req, res) => {
  const { page = 1, limit = 20, search } = req.query;

  const result = await userRepository.findActiveUsers(
    Number(page),
    Number(limit),
    search as string
  );

  // Check if empty
  if (result.isEmpty) {
    return res.json({
      data: [],
      meta: result.meta,
      message: "No users found",
    });
  }

  // Transform for API
  const response = result
    .map((user) => ({
      id: user.id.value,
      name: user.name,
      email: user.email,
      avatar: user.profile?.avatarUrl,
      joinedAt: user.createdAt.toISOString(),
    }))
    .toJSON();

  res.json(response);
});

fromArray() Behavior

When using fromArray(), the criteria is fully applied in memory:

const allProducts: Product[] = [...]; // 1000 products

const criteria = Criteria.create<Product>()
  .whereEquals("category", "electronics")  // Filter
  .where("price", "lessThan", 500)         // Filter
  .search(["name"], "laptop")              // Search
  .orderByDesc("rating")                   // Order
  .paginate(1, 20);                        // Paginate

const result = PaginatedResult.fromArray(allProducts, criteria);

// Process:
// 1. Apply search (finds matches across all items)
// 2. Apply filters (reduces to matching items)
// 3. Apply ordering
// 4. Calculate total from filtered results
// 5. Apply pagination (slice)
// 6. Return PaginatedResult with correct metadata

fromArray() loads all data into memory before filtering. Only use it for small datasets or testing. For production, implement filtering at the database level.

API Reference

Static Methods

Method	Parameters	Returns	Description
`create`	`data: T[], pagination: Pagination, total: number`	`PaginatedResult<T>`	Create with explicit metadata
`createMeta`	`pagination: Pagination, total: number`	`PaginationMeta`	Create metadata only
`fromArray`	`items: T[], criteria: Criteria<T>`	`PaginatedResult<T>`	Apply criteria to array

Instance Properties

Property	Type	Description
`data`	`T[]`	The result items
`meta`	`PaginationMeta`	Pagination metadata
`isEmpty`	`boolean`	True if no data
`hasMore`	`boolean`	True if more pages exist

Instance Methods

Method	Parameters	Returns	Description
`toJSON`	-	`PaginatedJsonResult<T>`	Deep serialize
`map`	`fn: (item: T) => U`	`PaginatedResult<U>`	Transform items

Getting Started

Core Concepts

Validation

Change Tracking

Repository

Integrations

Overview

Creating PaginatedResult

From Repository

Manual Creation

From Array (Testing/In-Memory)

PaginationMeta Structure

Accessing Metadata

Creating Metadata Manually

Utility Properties

isEmpty

hasMore

Transforming Results

map()

Chaining map()

Serialization

toJSON()

What Gets Serialized

Type Safety

API Response Pattern

Complete Example

fromArray() Behavior

API Reference

Static Methods

Instance Properties

Instance Methods

Getting Started

Core Concepts

Validation

Change Tracking

Repository

Integrations

​Overview

​Creating PaginatedResult

​From Repository

​Manual Creation

​From Array (Testing/In-Memory)

​Pagination Metadata

​PaginationMeta Structure

​Accessing Metadata

​Creating Metadata Manually

​Utility Properties

​isEmpty

​hasMore

​Transforming Results

​map()

​Chaining map()

​Serialization

​toJSON()

​What Gets Serialized

​Type Safety

​API Response Pattern

​Pagination UI Example

​Complete Example

​fromArray() Behavior

​API Reference

​Static Methods

​Instance Properties

​Instance Methods

Overview

Creating PaginatedResult

From Repository

Manual Creation

From Array (Testing/In-Memory)

Pagination Metadata

PaginationMeta Structure

Accessing Metadata

Creating Metadata Manually

Utility Properties

isEmpty

hasMore

Transforming Results

map()

Chaining map()

Serialization

toJSON()

What Gets Serialized

Type Safety

API Response Pattern

Pagination UI Example

Complete Example

fromArray() Behavior

API Reference

Static Methods

Instance Properties

Instance Methods