Transformer

Transformer helps to convert plain objects into classes and back. Transformable classes can use pre-compiled transformers which makes this transition fast.

Installation

Usage example

import {
  Transformable,
  TProperty,
  Transformer,
  MapConverter
} from '@poq/transform';

// For undefined values null will be set.
@Transformable({ nullify: false })
class License {
  // Defines property level default value.
  @TProperty({ defaultValue: 'Default term' })
  readonly terms: string;

  @TProperty()
  readonly signed: boolean;

  @TProperty({ type: Date })
  readonly verified: Date | null;
}

@Transformable()
class User {
  @TProperty() readonly name: string;
  @TProperty() readonly age: number;
}

@Transformable()
class OrgDocument {
  @TProperty({ type: new MapConverter(User) })
  readonly executives: Map<string, User>;

  @TProperty({ name: 'workers', type: [User] })
  readonly employees: User[];

  @TProperty({ type: License })
  readonly workLicense: License;
}

// Used to speed up transformer functions for registered classes.
Transformer.precompile();

const plainObj = {
  workLicense: {
    terms: 'some terms',
    signed: true,
    verified: '2021-09-04T08:45:18.910Z'
  },
  workers: [
    { name: 'Sam Sam', age: 24 },
    { name: 'Jack Apple', age: 19 }
  ],
  executives: {
    'John MackDuck': { name: 'John MacDuck', age: 35 },
    'John Doe': { name: 'John Doe', age: 39 }
  }
};

const document = Transformer.toType(plainObj, OrgDocument);
console.dir(document);
/*
result:

OrgDocument {
  employees: [
    User { name: 'Sam Sam', age: 24 },
    User { name: 'Jack Apple', age: 19 }
  ],
  executives: Map(2) {
    'John MackDuck' => User { name: 'John MacDuck', age: 35 },
    'John Doe' => User { name: 'John Doe', age: 39 }
  },
  workLicense: License {
    terms: 'some terms',
    signed: true,
    verified: 2021-09-04T08:45:18.910Z
  }
}
*/