TypeScript Automapper

Inspired by MaDEiN83 mapper

Installation

$ npm install ts-mapper

Usage

Create map

To create a mapping between two objects, you must call the object method createMap of the TypeMapper class.

It takes two interfaces:

• first interface must be the source interface
• second interface must be the destination interface

So, if we have an object of type ISource and we want a object of type IDestination, we should create a new mapping like that:

import { TypeMapper } from "ts-mapper";
import { ISource, IDestination } = "../path/of/interfaces.ts";

export class Mapper extends TypeMapper {
   constructor() {
      super();
      this.config();
   }

   private config(): void {
      // put here your mapping configurations
      this.createMap<ISource, IDestination>();
   }
}

const mapper = new Mapper();

Map fields

After we create a mapping between interfaces, we can now create all mappings between all wanted properties of our objects (source & destination).

For example, if we want to map the property sourceObject.srcOther to destinationObjet.other, we can define rule like that:

mapper.createMap<ISource, IDestination>();
  .map(src => src.srcProperty, dest => dest.destProperty)
  .map(src => src.srcOther, dest => dest.other);

• src type is ISource
• dest type is IDestination

You can chain your rules !

Conditionnal mapping

conditions method allows you to check if the previous map will be analysed and mapped to the destination object.

Example: We want to map the property srcProperty (source object) into destProperty (destination object) only if the property visible of the source object is true.

mapper.createMap<ISource, IDestination>();
  .map(src => src.srcProperty, dest => dest.destProperty)
  .conditions((s: ISource) => s.visible);

The conditions method takes two arguments:

• the source object
• the destination object

Examples:

mapper
   .createMap<ISource, IDestination>()
   .map(src => src.my_prop, dest => dest.myProp)
   .conditions((s: ISource, d: IDestination) => s.visible);

mapper
   .createMap<ISource, IDestination>()
   .map(src => src.my_prop, dest => dest.myProp)
   .conditions((s: ISource, d: IDestination) => s.visible !== d.visible);

Fly and Casts

Sometime the source properties don't match the destination properties.

Example: sourceObject.age can be a string and destinationObject.age is a number.

To work with, you can cast property by chaining the is method after a map.

import { TypeMapper, AutoMapperTypes } from "ts-mapper";

mapper
   .createMap<ISource, IDestination>()
   .map(p => p.age, p => p.age)
   .is(AutoMapperTypes.NUMBER);

Execution and Mapping

mapper
   .createMap<ISource, IDestination>()
   .map(p => p.name, p => p.name)
   .is(AutoMapperTypes.STRING);

const source: ISource = {
   name: "Marluan",
   email: "[email protected]",
   password: "my_sup3r_s3cr3t_p455w0rd"
};

const destination: IDestination = { name: null };

mapper.map<ISource, IDestination>(source, destination);

console.log(destination);
// {
//    name: "Marluan";
// }