Immute

Description

Immute is a simple library intended for the creation of immutable value objects. If you want to know more about what immutable value objects are and why they a good thing have, please read the following article by Runway 7.

Installation

Immute is available from the NPM repository simply npm install immute or add immute as a dependency in your package.json file.

Usage

Creating immutable object constructor

var immute = require('immute');

var Cat = immute({
        name: "required",
        birthDate: "required",
        description: "optional"
    });

Object properties can be required or optional

var unknown = new Cat({birthDate: "02.03.32", description: "fat homeless cat"}); 
// ERROR: 'Required field missing from immutable object'

Object properties cannot be updated

var sheldon = new Cat({name: "sheldon", birthDate: "02.04.2013"}); //valid
sheldon.name = "Leonard"; // ERROR: 'Immutable value object. Property cannot be changed'

Objects are closed so no additional parameters can be added

var cuddles = new Cat({name: "cuddles", birthDate: "02.02.2012", description:"likes salmon"}); //valid
cuddles.status = "sleeping"; 

Object.keys(cuddles); // ['name','birthDate','description']