TypeProperties

The TypeProperties is an experimental project that should help you create better TypeScript NodeJS Rest APIs. It enables you to create serializeable models that are JSON type safe and fully type checked.

The TypeProperties is a solution for "writing type once", this is particularly useful when Metadata Reflect API is not enough, as Reflect is only coerce when types are solely based on typeof and instanceof. In all the other cases when you wrap your type into an array or make it nullable with union types, Reflect stops preserving types.

Example usage

import {  
  Properties,
  Property,
  Factory,
  Nullable,
  ListOf,
  Descr,
  Default,
} from '@type-properties/core';

enum UserStatus {
    ACTIVE = 0;
    INACTIVE = 1;
}


@Properties()  
export class UserProps extends UserIdentifierProperties {  
    
  @Descr('The user id')  
  id = Property[0](
    type => String,
  );  
  
  @Descr(`The user email`)  
  email = Property[3](
    type => Nullable(String),
  );  
    
  @Descr(`The user given name`)  
  givenName = Property[1](
    type => String,
  );  
    
  @Descr(`The user family name`)  
  familyName = Property[2](
    type => String,  
  );  
    
  displayName = Property[4](  
    type => String,  
    init => `${this.givenName} ${this.familyName}`,
  );  
    
  @Default(value => new Date()) 
  registeredAt = Property[5](
    type => Date,
  );  
    
  followers = Property[6](
    type => ListOf(User),
    init => [],
  );
  
  @Default(value => 'ACTIVE')
  status? = Property[7](
    type => UserStatus,
  );

}  
  
@Descr(`The user type`)  
export class User extends Factory(UserProps) {}  
  
const user = new User({  
  id: '1',  
  givenName: 'John',  
  familyName: 'Doe',  
});  
  
const parsedUser = User.fromJSONString(JSON.stringify(user));

if (
  parsedUser instanceof User
    && parsedUser instanceof UserProps,
    && parsedUser.registeredAt instanceof Date // witch means it unserializes Date objects
) {  
  // this will be true  
}

TypeProperties gives you more abstraction to model types

// Static members
export interface UserStatic {
  /**
   * The properties class
   */
  Properties: UserProperties;
  /**
   * The properties factory serializer
   */
  Serializer: JSONSerializer;

  /**
   * Get factory property definitions
   */
  getProperties(): ArrayLikePropertyDefinitions;

  /**
   * Get factory property names
   */
  getPropertyNames(): TupleKeys<UserProperties>;

  /**
   * Transform plain object to properties factory
   * @param obj
   */
  fromPlainObject(obj: PlainObject<UserProperties>): User;

  /**
   * Transform json serialized object into properties factory
   * @param json
   */
  fromJSON(json: { [key: string]: any } | any[]): User;

  /**
   * Transform json serialized string into properties factory
   * @param jsonString
   */
  fromJSONString(jsonString: any): User;

  /**
   * Transform property tuple values into properties factory
   * @param values
   */
  fromValues(values: TupleValues<UserProperties>): User;

  /**
   * Transform property tuple values into properties factory with strict values
   * @param values
   */
  fromStrictValues(values: StrictTupleValues<UserProperties>): User;

  /**
   * Encodes properties factory to base64 string
   * @param forge
   * @param encoding
   */
  stringify(forge: Forge<UserProperties>, encoding?: 'hex' | 'base64'): string;

  /**
   * Parse a base64 string into properties factory
   * @param str
   * @param encoding
   */
  parse(str: string, encoding?: 'hex' | 'base64'): User;

  /**
   * Encodes properties factory into array of bytes
   * @param forge
   * @param encoding
   */
  encode(forge: Forge<UserProperties>): Uint8Array;

  /**
   * Decodes array of bytes into properties factory
   * @param bytes
   */
  decode(bytes: Uint8Array): User;
}

// Prototype members
interface User {
  /**
   * Transform properties factory into tuple of property values
   */
  toValues(): TupleValues<UserProperties>;

  /**
   * Return all property keys
   */
  toKeys(): TupleKeys<UserProperties>;

  /**
   * Transform properties factory into plain object
   */
  toPlainObject(): PlainObject<UserProperties>;

  /**
   * Transform properties factory into json ready object
   */
  toJSON(): { [key: string]: any };

  /**
   * Transform properties factory into json ready tuple of values
   */
  toJSONValues(): any[];

  /**
   * Stringify
   * @param encoding
   */
  stringify(encoding?: 'hex' | 'base64'): string;

  /**
   * Transform serializeable factory into bytes
   */
  encode(): Uint8Array;
}