Sugared DOM: Better Than Templates

gistfile1.js

var el = ( function () {

var doc = document;

var directProperties = {
    'class': 'className',
    className: 'className',
    defaultValue: 'defaultValue',
    'for': 'htmlFor',
    html: 'innerHTML',
    text: 'textContent',
    value: 'value'
};

var booleanProperties = {
    checked: 1,
    defaultChecked: 1,
    disabled: 1,
    multiple: 1,
    selected: 1
};

var setProperty = function ( el, key, value ) {
    var prop = directProperties[ key ];
    if ( prop ) {
        el[ prop ] = ( value == null ? '' : '' + value );
    } else if ( booleanProperties[ key ] ) {
        el[ key ] = !!value;
    } else if ( value == null ) {
        el.removeAttribute( key );
    } else {
        el.setAttribute( key, '' + value );
    }
};

var appendChildren = function ( el, children ) {
    var i, l, node;
    for ( i = 0, l = children.length; i < l; i += 1 ) {
        node = children[i];
        if ( node ) {
            if ( node instanceof Array ) {
                appendChildren( el, node );
            } else {
                if ( typeof node === 'string' ) {
                    node = doc.createTextNode( node );
                }
                el.appendChild( node );
            }
        }
    }
};

var splitter = /(#|\.)/;

var create = function ( tag, props, children ) {
    if ( props instanceof Array ) {
        children = props;
        props = null;
    }
    
    var parts, name, el,
        i, j, l, node, prop;
    
    if ( splitter.test( tag ) ) {
        parts = tag.split( splitter );
        tag = parts[0];
        if ( !props ) { props = {}; }
        for ( i = 1, j = 2, l = parts.length; j < l; i += 2, j += 2 ) {
            name = parts[j];
            if ( parts[i] === '#' ) {
                props.id = name;
            } else {
                props.className = props.className ?
                    props.className + ' ' + name : name;
            }
        }
    }
    
    el = doc.createElement( tag );
    if ( props ) {
        for ( prop in props ) {
            setProperty( el, prop, props[ prop ] );
        }
    }
    if ( children ) {
        appendChildren( el, children );
    }
    return el;
};

return create;

}() );

Using instanceof is not a recommended way to check whether a value is an array. http://perfectionkills.com/instanceof-considered-harmful-or-how-to-write-a-robust-isarray/

Unless you're using multiple frames, instanceof works perfectly and is faster than using the Object.prototype.toString method. Obviously, if you are calling this method from a different frame and passing an array created within the iframe, then the instanceof check won't work. If this situation applies to you though, you also probably want to add an (optional) extra argument to pass in the document object for the frame you want to create the elements for; at the moment this is captured in the closure to be the document where the script is originally loaded.

What conditions have to be met to use this in own projects?