es6-model v1.0.2

es6-model

ES6-model is a simple base-class helper designed for data-models in JavaScript.

Prerequisites

As this package use the class ES6-based syntax, your app needs to integrate an ES6-compatible transpiler like Babel.

Additionally, you'll need to install this Babel package to make your models working: @babel/plugin-proposal-class-properties.

Note: This package is currently needed because the "class properties" concept is not an official ECMA standard yet. This repo will be updated when the standard will become available.

Installation

npm

npm install es6-model --save-dev

yarn

yarn add -d es6-model

Usage

Import es6-model in your code where you want to define your app's models, then use it as a base class.

// Import es6-model
import Model from 'es6-model'

// Extends the base class to create your own
class Pet extends Model {
  // ...
}

// You can also extend your own model-based classes
class Cat extends Pet {
  // ...
}

Declare your class properties, then in your constructor method, pass them to the super magic method call before assigning them.

class Pet extends Model {
  // Declare your class properties
  name = null
  age = null

  constructor (name, age) {
    super({
      name: [name, String],
      age: [age, Number]
    })

    this.name = name
    this.age = age
  }
}

By calling the es6-model constructor method with super(), several type & value checkings will be performed on your constructor arguments. This will force your model data to be strictly the types you define.

Documentation

Your constructor arguments must be passed to the super() method through an object, with each field representing an argument with its associated constraints:

propName: [propValue, propType, propRequired]

propName

Name of the property you want to assign (same as the corresponding argument name).

propValue

The property value, directly retrieved from the constructor arguments.

propType

The type you want to use for the argument.

propRequired

A boolean indicating if the property is required or not.
A required property tells the Base Model to check if the value is different from null and undefined.

constructor (name, children) {
  super({
    name: [name, String, true], // required property
    children: [children, Array] // optional property
  })
}

You can also provide a custom object type.

class Pet extends Model {
  // ...
}

constructor (pet) {
  super({
    // Declare 'pet' prop to be a <Pet> object
    pet: [pet, Pet, true]
  })
}

Sometimes you want to use an array as value, but what if you want to restrict your array to a specific type?

class People extends Model {
  // ...
}

constructor (children) {
  super({
    // Declare 'children' prop to be an Array of <People> objects
    children: [children, { Array: People }, true]
  })
}

In some cases, we also want to accept multiple types for a given property.

constructor (id) {
  super({
    // Declare 'id' prop to be either a Number or a String
    id: [id, [Number, String], true]
  })
}

Examples

You can see a demo of this package by running these commands in the project root:

yarn install
yarn start

Go to http://localhost:<PORT>/examples/, and select an example directory.

License

MIT