Type-Mapper - Declarative Mapping Between Untyped Data and JavaScript Classes

If you have untyped data in JavaScript, from JSON.parse for example, and you want to transform it into a JavaScript class using a combination of constructor arguments and properties, then type-mapper is a solution.

Installation

npm install @sflanker/type-mapper

Usage

Given some untyped data:

{
  "make": "Ford",
  "model": "Mustang",
  "year": 1969
}

Decorate your class using Type-Mapper:

import { mapped, alias, required, defaultValue } from '@sflanker/type-mapper';

class Vehicle {
    @mapped
    public year: number = 0

    constructor(
        @alias('make')
        @alias('manufaturer')
        @required
        public make: string,
        @alias('model')
        @defaultValue('UNKNOWN')
        public model: string) {
    }
}

Then use Mapper to convert your untyped data to an instance of your class:

import { Mapper } from '@sflanker/type-mapper'

const myVehicle = Mapper.convert(Vehicle, myData)

Features

• Complex Types (via the typeOf and arrayOf decorators)
• Mapping nested data via simple "dot" syntax
• Mapping Arrays -> Objects via Positional Arguments
• Required fields and Default Values
• Validation
• Transformation