TypeScript Traits

A lightweight, strictly typed utility for class composition (Traits/Mixins) in TypeScript. It allows you to combine a Base Class with multiple Trait Classes.

Requirements

• Typescript version 4.9 or higher

Installation

npm install github:daniloivk/ts-traits

Example usage

/**
 * Class with common properties if any
 */
class Model {
  constructor(public readonly id: number, public readonly name: string) {}
}

/**
 * Class to apply traits to
 */
class RoleModel extends Model {
  constructor(public readonly id: number, public readonly name: string) {
    super(id, name);
  }
}

/**
 * Traits
 *
 * - Can declare properties and/or function
 */
class Comparable extends Model {
  public is(other: this): boolean {
    return this.id === other.id;
  }
}

class Stringable extends Model {
  public toString(): string {
    return (this as any).name;
  }
}

/**
 * Class with traits applied
 */
const Role = withTraits(RoleModel, Comparable, Stringable);

/**
 * New class instances
 */
const adminRole = new Role(1, 'Admin');
const userRole = new Role(2, 'User');

/**
 * Trait functionalities usage
 */
console.table(adminRole);
console.table(userRole);

console.info(
  `${adminRole} === ${userRole} ?`,
  adminRole.is(userRole) ? 'true' : 'false'
);