Data Controller Module

Data Controller is browser module that aims to let implementations to know about data updates inside a data attribute of a host object in a simple way.

It uses a Proxy to capture any modification in the target data and comunicates changes dispatching an event called dataUpdated.

Installing

npm i @modnes/data-controller

Usage

The Data Controller must receive an object that implements the EventTarget interface for to it be able to dispatch events. This means it can be used within custom elements for example. ;-)

import DataController from "path/to/modnes-data-controller/data-controller.js"

class Host extends EventTarget {}

let host = new Host()
let dataController = new DataController(host)

host.addEventListener('dataUpdated', event => {
  console.log(event.detail)
})

host.data = {
  id: 100,
  text: 'String'
}

host.data.text = 'Modified String'

Methods

Data Controller provides more two main methods: bindDOM() and bindForm(). These methods allow building applications using the Two Way Data Binding idea.

bindDOM

The bindDOM() method uses an array containing mapping set that bind properties modifications to elements in DOM. Each map must to set the property attribute from data in the host object.

The following are some examples of configuring mappings:

const MAPPING_SET = [
  {
    property: 'id',
    elements: document.querySelector('#test'),
    attributes: 'id'
  },
  {
    property: 'date',
    elements: document.querySelector('.dates'),
  },
  {
    property: 'person.name',
    elements: 'div#person',
    attributes: ['title'],
    template: '<h1>{{ value }}</h1>'
  },
  {
    property: 'person.age',
    elements: 'div#person span.age',
    attributes: ['data-age']
  },
  {
    property: 'person.active',
    elements: 'div#person .active',
    attributes: ['data-active']
  },
  {
    property: 'person.bio',
    elements: 'div#person .bio',
    template: value => `<blockquote>${value}<blockquote>`
  }
]

dataController.bindDOM(MAPPING_SET)

bindForm

The bindForm() receives a form and binds each form element to a property from data by it name attribute.

<form class="person-form">
  <input type="text" name="person.name" />
  <input type="range" name="person.age" />
  <input type="text" name="person.bio" />
  <input type="checkbox" name="person.active" />

  // Values as Array
  <input type="checkbox" name="person.roles" value="admin" />
  <input type="checkbox" name="person.roles" value="manager" checked />
  <input type="checkbox" name="person.roles" value="user" checked />

  // person.favoritePosts is an array of objects with id property set to this values
  // Use the data-as-number attribute to use the value as Number type
  <select name="person.favoritePosts.id[]" data-as-number multiple>
    <option value="1">Post 1</option>
    <option value="2" selected>Post 2</option>
    <option value="3" selected>Post 3</option>
  </select>
</form>

let form = document.querySelector('.person-form')

dataController.bindForm(form)

See the API documentation