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An element authoring library for creating standalone and performant elements.

build status NPM version experimental

Sauce Test Status

View this example List element in use with:

Or other examples:

example usage

You can construct your element API however you choose. A way that I prefer is by inheriting prototypes:

var BaseElement = require('base-element')
function Bear () {
Bear.prototype = Object.create(BaseElement.prototype)
// Or inherits(Bear, BaseElement) 
// Or class Bear extends BaseElement 

Then build your elements:

Bear.prototype.render = function (typeOfBear) {
  // Create a virtual DOM tree 
  var vtree = this.html('div.bear', ['Im a ' + typeOfBear + '!'])
  // Call afterRender with your vtree when returning your vtree 
  return this.afterRender(vtree)

Prefer just functions?

If you prefer just functions, an alternative interface is available:

var createElement = require('base-element')
// Create an element on a parent 
var el = createElement(document.body)
el.render(function () {
  // Render a button upon clicked will alert 
  return el.html('button', {
    onclick: function (e) {
      window.alert( + ' button was clicked')
  }, 'click me')

data down, events up

DOMs work best (in the opinion of myself and many) when data goes down and event (or actions) go up.

A simple example is a button element that changes when clicked. How it changes is up to the element but what it changes to is up to the user.

This is our Button element:

var BaseElement = require('base-element')
function Button () {
Button.prototype = Object.create(BaseElement.prototype)
// Or inherits(Button, BaseElement) 
// Or class Button extends BaseElement 
Button.prototype.render = function (label) {
  var self = this
  // The "label" data is coming down 
  var vtree = this.html('button', {
    onclick: function (event) {
      // We send the "clicked" event up 
  }, label)
  return this.afterRender(vtree)

and this is the user's implementation, creates a button and on every click it changes to a random number:

var button = require('your-button')()
button.addEventListener('clicked', function (node) {
  button.render('button label ' + Math.random())

nested architecture

Elements created using base-element are intended on being shared and extended by others. Each element should not require an additional library/framework to run it or be injected into it in order to be ran. Elements should be standalone.

For example if you create an input-box element and published on npm:

var BaseElement = require('base-element')
function InputBox (el) {, el)
InputBox.prototype = Object.create(BaseElement.prototype)
module.exports = InputBox
InputBox.prototype.render = function (value) {
  // Builds an <input value="{value}: /> 
  return this.afterRender(this.html('input', {
    onkeyup: function(e) {
      // When keys are typed in it we send the value up 
    value: value || ''

Later yourself or another user can extend input-box to add functionality on top, such as email-input:

var InputBox = require('input-box')
function EmailInput (el) {, el)
  // When we receive a "changed" event from InputBox, handle it here 
  this.addEventListener('changed', function (text) {
    /* Perform some email validation on text here,
       then render() if we need an update */
EmailInput.prototype = Object.create(InputBox.prototype)
module.exports = EmailInput
EmailInput.prototype.render = function (data) {
  data = data || {}
  var vtree = this.html('div', [
    // Put a <label>Enter your email</label> inside this <div> 
    this.html('label', data.label || 'Enter your email'),
    // Call the InputBox's render 
  // Return the virtual DOM tree 
  return this.afterRender(vtree)

Both input-box and email-input can be ran on their own. When input-box updates over time, email-input can stay on a previous version until an upgrade can be made.


npm with browserify, webpack, etc

  • npm install base-element
  • var BaseElement = require('base-element')


  • copy/download/etc dist/base-element.js
  • <script src="base-element.js"></script>
  • <script>var element = new BaseElement()</script>


var element = new BaseElement([attachTo])

attachTo is a DOM element you want to append to such as document.body

By default, the element will not attach itself to a parent node. This is useful for handling the rendering on your own.

element.send(name[, params...])

Sends an event up with a given name and params.

element.addEventListener(name, function)

Register an event listener for a given name:

element.addEventListener('clicked', function (params) {})


This method needs to be called when returning a constructed virtual tree. It will detect if we are at the top of the render tree and perform the DOM diff and patching.

Button.prototype.render = function (data) {
  var vtree = this.html('button')
  return this.afterRender(vtree)

element.html(tag[, options], value)

A convenience wrapper for creating virtual-hyperscript nodes, i.e.:

var h = require('virtual-dom/h')
var vtree = h('div', 'Testing')
// is the same as 
var vtree = this.html('div', 'Testing')


For rendering your element as a string of HTML. data is any initial data passed to your render function.


The root DOM node the virtual tree resides on.


The current virtual DOM tree of the base element.

default events

load and unload events will be sent by default if your top level element registers this as it's properties:

var BaseElement = require('base-element')
function Button(el) {, el)
  this.addEventListener('load', function (node) {
    console.log(node + ' has loaded!')
  this.addEventListener('unload', function (node) {
    console.log(node + ' has unloaded!')
Button.prototype.render = function (data) {
  // The top level element is provided with `this`, events will be fired 
  return this.afterRender(this.html('button', this, 'click me'))


(c) 2015 Kyle Robinson Young. MIT License