declarative classSet for jquery (just for concept)

makeClassSet.coffee

# global helper
makeClassSet = (classFunc) ->
	return (params) ->
		classArr = []
		for className, exp of classFunc(params)
			classArr.push(className) if exp

		return classArr.join(' ')

# local helper
getColorClasses = makeClassSet(({somePredicate, size}) -> 
	return {
		'is-danger': not somePredicate
		'is-success': somePredicate
		'is-big': size >= 20
		'is-normal': size > 10 and size < 20
		'is-small': size <= 10
	}
)

# logic
console.log getColorClasses({inJson: false, size: 16})