cre

cre

Micro-framework for constructing DOM nodes.

cre is, effectively, a better document.createElement, one that will also work as document.createDocumentFragment when given an array of nodes to insert into the fragment, or document.createTextNode when given an array of only one string.

Its interface is similar to FastMail's el function, or crel, which I only found by searching for names I might give this.

Usage

Pardon our dust: This documentation needs some work (it is, after all, a pre-1.0 package): for now, here's a simple example that demonstrates the basic functionality of this module (courtesy this tweet):

import cre from 'https://unpkg.com/cre@0.3.0/cre.js';
function render() {
  document.querySelector('#main').appendChild(cre('h1.big', 'header'));
}
document.addEventListener('DOMContentLoaded', render);

Setting options

cre also supports setting attributes and properties on the created element on creation, as well as adding event listeners, by adding an additional parameter with an object of options.

By default, this options object's own properties will be set accordingly on the created element in its creation, with the following exceptions:

• namespaceURI and is are only used during element creation and not assigned to the element itself.
• className and classList receive special handling so that they may be mixed together, along with class specifiers in the "tag name" specifier.
• Properties of style are applied recursively.
• attributes applies a series of objects with name and value property pairs to the element (this interface will likely change soon).
• Properties of on are treated as event names, and addEventListener is called on either the value of the property, or of every value of the array in the property. Listeners that need to be added with options can provide an object with those options as properties, and the listener specified as the listener method of the property.

Effective use

cre works best when you're passing it to appendChild or insertBefore. cre also works best when you use it to clone templatized nodes, rather than constructing new elements from scratch every time (because cloning DOM nodes is faster than creating elements from scratch).

Examples

Here are just a few of the things you can do easily with cre, which would otherwise be somewhat verbose and annoying:

Making template elements

(this example is taken directly from the source code for the Tabalanche Chrome extension)

var templateTabIcon = cre('img.tabicon');
var templateTabLink = cre('a.tablink');
var templateTabListItem = cre('li.tablist-item');
var templateTabStash = cre('div.tabgroup.tabstash');
var templateFlap = cre('div.flap');
var templateTabList = cre('ul.tablist');

Cloning and populating templates

(this example is also taken directly from the source code for the Tabalanche Chrome extension)

function createTabListItem(tab) {
  var tabIcon = cre(templateTabIcon,
    {src: tab.icon || platform.faviconPath(tab.url)});

  var tabLink = cre(templateTabLink, {href: tab.url},
    [tabIcon, tab.title]);

  var listItem = cre(templateTabListItem, [tabLink]);

  /* (event listener code omitted for brevity) */

  return listItem;
}

Appending a text node to an element and manipulating it

var statusMessage = cre([' This message will self-destruct in five seconds.'])
var paragraphs = document.getElementsByTagName('p');
var lastParagraph = paragraphs[paragraphs.length-1];
lastParagraph.appendChild(statusMessage);
setTimeout(function(){
  statusMessage.textContent = ' This message has self-destructed. Have a nice day.'
}, 5000);

Creating a document fragment with spans of text and inserting it

function payItForwardWarning(favorCount) {
  return cre(['You have ', cre('span.favor-count', favorCount*3), ' favors to pay forward'])
}

var alertTicker = document.getElementById('alerts');
var firstMiscThingInTicker = alertTicker.querySelector('.misc');
var freshWarning = payItForwardWarning(user.favorsReceived);
alertTicker.insertBefore(freshWarning, firstMiscThingInTicker);

Using cre for another document

import CreContext from "cre";

const foreignCre = new CreContext(foreignDocument);