color.js

const Color = {
	split( col ) {
		switch ( col[ 0 ] ) {
			case "r": return ( col[ 3 ] === "a"
				? Color._rgbaExtract
				: Color._rgbExtract )( col );
			case "#": return ( col.length < 6
				? Color._hex3Extract
				: Color._hex6Extract )( col );
		}
	},
	isDark( col ) {
		const [ r, g, b ] = Color.split( col );

		return ( r + g + b ) / 3 < 128;
	},

	// private:
	_rgbExtract( col ) {
		const rgb = col.substr( col.indexOf( "(" ) + 1 ).split( "," );

		rgb[ 0 ] = parseInt( rgb[ 0 ] );
		rgb[ 1 ] = parseInt( rgb[ 1 ] );
		rgb[ 2 ] = parseInt( rgb[ 2 ] );
		return rgb;
	},
	_rgbaExtract( col ) {
		const rgb = Color._rgbExtract( col );

		rgb[ 3 ] = parseFloat( rgb[ 3 ] );
		return rgb;
	},
	_hex6Extract( col ) {
		return [
			parseInt( col.substr( 1, 2 ), 16 ),
			parseInt( col.substr( 3, 2 ), 16 ),
			parseInt( col.substr( 5, 2 ), 16 ),
		];
	},
	_hex3Extract( col ) {
		const r = parseInt( col.substr( 1, 1 ), 16 ),
			g = parseInt( col.substr( 2, 1 ), 16 ),
			b = parseInt( col.substr( 3, 1 ), 16 );

		return [
			r * 16 + r,
			g * 16 + g,
			b * 16 + b,
		];
	},
};