Check out the interactive demo here!

What is CssJs?

CssJs is a micro css preprocessor that take Javascript objects and turns them into valid CSS. Taking advantage of nesting within js objects and the ability to use functions, let's you have powerful and clean CSS without having to learn another preprocessing language or even install anything!

CssJs doesn't depend on any other library. You can use it at run time by directly injecting your JS styles as a CSS tag in the page using css.render({..}). Or just output the string using css({...}) and save it to a css file.

Simple Example

Here's a basic example. Notice that you can either quote the rule if it has a dash in it, or you can just use camel casing.

var simpleCss = css({
	body: {
		marginTop: "20px",
		"margin-left": "20px",
		width: "100%"
	},
	header: {
		width: "100%"
	}
});

$(example).html('<pre>' + simpleCss + '</pre>')
		  .css('font-family', 'Courier');

Nesting

One of the most useful parts of using CSS preprocessors is being able to nest rules together, giving a better flow to your file.

var nestingIsHandy = css({
	body: {
		marginTop: "20px",
		width: "100%",
		p: {
			color: "#BADA55"
		}
	}
});

$(example).html('<pre>' + nestingIsHandy + '</pre>')
		  .css('font-family', 'Courier');

Pseudo-classes

It also handles pseudo-classes!

var pseudoPseudoPseudo = css({
	body: {
		a: {
			color: "#FFF",
			":hover": {
				textDecoration: "none"
			},
			":after": {
				display: "block",
				content: '"---"'
			}
		}
	}
});

$(example).html('<pre>' + pseudoPseudoPseudo + '</pre>')
		  .css('font-family', 'Courier');

Functions and Plugins

Since we're in Javascript let's leverage our ability to use some logic. CssJs automatically processes any functions it comes across. You can also declare variables and use those too. Plugins allow you to create your own custom CSS rules.

var themeColor = "#BADA55";
var textStyles = function(size) {
	return {
		color      : themeColor,
		fontSize   : size + "px",
		lineHeight : size + "px"
	}
}
css.plugins.coolPadz = function(pad){
	return {
		paddingTop    : pad*0.6 + 'px',
		paddingBottom : pad*0.6 + 'px',
		paddingLeft   : pad + 'px',
		paddingRight  : pad + 'px',
	}
}

var suchPower = css({
	body: {
		color: themeColor,
		p: textStyles(16),
		'.title' : {
			color: "#000",
			coolPadz : 40
		}
	}
})

$(example).html('<pre>' + suchPower + '</pre>')
		  .css('font-family', 'Courier');

#Color Write up some awesomeness using this lib, https://github.com/harthur/color. Here we're automatically creating the coloring for a button.

css.plugins.buttonColor = function(btnColor){
	btnColor = Color(btnColor)
	return {
		backgroundColor : btnColor.hexString(),
		color : btnColor.luminosity() < 0.9 ? 'white' : 'black',
		border : "1px solid " + btnColor.darken(0.3).hexString(),
		cursor : 'pointer',
		':hover' : {
			backgroundColor : btnColor.lighten(0.3).hexString()
		},
		'.pressed' : {
			backgroundColor : btnColor.darken(0.3).hexString()
		}
	}
}

var colorfulButton = css({
	'.loginBtn' : {
		marginRight : '10px',
		buttonColor: '#2ecc71'
	}
})

$(example).html('<pre>' + colorfulButton + '</pre>')
		  .css('font-family', 'Courier');

#Conversion If you already have some existing CSS that you want to trun into JSON you can use the css.toJSON() command to convert css strings.

<textarea id='cssString'>
.navbar{
	height           : 53px;
	margin-bottom    : 25px;
	background-color : #ecf0f1;
	font-size        : 16px;
	color            : #2C3E50;
}
.navbar:hover{
	color : #16A085;
}
</textarea>

And the code to convert it.

var cssAsJSON = css.toJSON($('#cssString').val());

$(example).html('<pre>' + JSON.stringify(cssAsJSON, null, '\t') + '</pre>')
		  .css('font-family', 'Courier');

Customization

By default CssJs uses a tab to space out it's generated CSS, but by changing the css.space variable to can change it to whatever you like.

css.space = '  '; //just two spaces

var customSpacing = css({
	body: {
		marginTop: "20px",
		"margin-left": "20px",
		width: "100%"
	},
	header: {
		width: "100%"
	}
});

$(example).html('<pre>' + customSpacing + '</pre>')
		  .css('font-family', 'Courier');

Sheet Creation

A neat workflow using CssJs is to use the css.render({...}) function while testing and developing to automatically generate you a style sheet and add it to your page. When you're happy with the results, simply use css({...}) to generate the CSS string and save it to your own file for production. No need to preprocess all the time!

css.render({
	'#coolDiv' :{
		color : 'green'
	}
});

$(example).html('<div id="coolDiv">Coolest green div around</div> <div>Not so green :(</div>');