Features

A comprehensive set of decorators covering immutability, boilerplate reduction, and common design patterns.

ImmutabilityBoilerplateConstructorsPatternsValidation

3Immutability

@Record

Creates an immutable data carrier with constructor, readonly properties, Object.freeze, and toString.

1@Record
2class User {
3  id: number;
4  name: string;
5}
6
7const user = new User(1, 'John');
8console.log(user.toString()); // User(id=1, name=John)
9console.log(Object.isFrozen(user)); // true

@Value

Alias for @Record. Creates an immutable value class.

1@Value
2class Point {
3  x: number;
4  y: number;
5}
6
7const p = new Point(10, 20);

@With

Generates withX() methods for creating modified copies of immutable objects.

1@Record
2@With
3class User {
4  id: number;
5  name: string;
6}
7
8const user = new User(1, 'John');
9const updated = user.withName('Jane');
10
11console.log(user.name);    // 'John' (unchanged)
12console.log(updated.name); // 'Jane' (new instance)

4Boilerplate

@Data

Combines @Getter + @Setter + @ToString + @Equals + @AllArgsConstructor for complete data class functionality.

1@Data
2class User {
3  id: number;
4  name: string;
5}
6
7const user = new User(1, 'John');
8user.getId();           // 1
9user.setName('Jane');
10user.toString();        // User(id=1, name=Jane)
11user.equals(other);     // true/false
12user.hashCode();        // number

@Getter / @Setter

Generate getter and setter methods for all properties.

1@Getter
2@Setter
3class User {
4  id: number;
5  name: string;
6}
7
8const user = new User();
9user.setId(1);
10user.setName('John');
11console.log(user.getId());   // 1
12console.log(user.getName()); // 'John'

@ToString

Generates a toString() method that includes all fields.

1@ToString
2class User {
3  id: number;
4  name: string;
5}
6
7const user = new User();
8user.id = 1;
9user.name = 'John';
10console.log(user.toString()); // "User(id=1, name=John)"

@Equals

Generates value-based equals() and hashCode() methods.

1@Equals
2class Point {
3  x: number;
4  y: number;
5}
6
7const p1 = new Point(); p1.x = 1; p1.y = 2;
8const p2 = new Point(); p2.x = 1; p2.y = 2;
9
10p1.equals(p2);                     // true
11p1.hashCode() === p2.hashCode();   // true

3Constructors

@NoArgsConstructor

Generates an empty constructor.

1@NoArgsConstructor
2class Config {
3  host: string;
4  port: number;
5}
6
7const config = new Config();
8config.host = 'localhost';
9config.port = 3000;

@AllArgsConstructor

Generates a constructor with all fields as parameters.

1@AllArgsConstructor
2class Point {
3  x: number;
4  y: number;
5  z: number;
6}
7
8const p = new Point(1, 2, 3);

@RequiredArgsConstructor

Generates a constructor with only required fields (non-optional, no initializer).

1@RequiredArgsConstructor
2class User {
3  id: number;              // Required - in constructor
4  name: string;            // Required - in constructor
5  active: boolean = true;  // Has initializer - excluded
6  nickname?: string;       // Optional - excluded
7}
8
9const user = new User(1, 'John');
10console.log(user.active); // true (default value)

3Patterns

@Builder

Implements the builder pattern with a fluent API for object construction.

1@Builder
2class User {
3  id: number;
4  name: string;
5  email: string;
6}
7
8const user = User.builder()
9  .id(1)
10  .name('John')
11  .email('john@example.com')
12  .build();

@Singleton

Ensures only one instance exists via getInstance() static method.

1@Singleton
2@NoArgsConstructor
3class AppConfig {
4  apiUrl: string = 'https://api.example.com';
5}
6
7const config1 = AppConfig.getInstance();
8const config2 = AppConfig.getInstance();
9console.log(config1 === config2); // true

@Log

Generates a protected logger field using console.

1@Log
2class UserService {
3  createUser(name: string) {
4    this.log.info(`Creating user: ${name}`);
5    // ...
6  }
7}

1Validation

@NonNull

Property decorator that validates fields are not null/undefined in the constructor.

1@AllArgsConstructor
2class User {
3  @NonNull
4  id: number;
5
6  @NonNull
7  name: string;
8}
9
10new User(1, 'John');     // OK
11new User(null, 'John');  // Throws: "id cannot be null or undefined"

Combining Decorators

Decorators can be combined for full functionality. Mix and match to get exactly what you need:

1import { Record, Equals, With, Builder } from 'ts-lombok-kit/markers';
2
3@Record
4@Equals
5@With
6@Builder
7class Product {
8  id: number;
9  name: string;
10  price: number;
11}
12
13// Create with builder
14const p1 = Product.builder()
15  .id(1)
16  .name('Widget')
17  .price(9.99)
18  .build();
19
20// Immutable update
21const p2 = p1.withPrice(19.99);
22
23console.log(p1.equals(p2));      // false (different prices)
24console.log(p1.toString());      // Product(id=1, name=Widget, price=9.99)
25console.log(Object.isFrozen(p1)); // true

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