`classnames`, but emitting an object instead of a string.

classnames-object.js

var hasOwn = {}.hasOwnProperty

function writeClasses() {
    for (var i = 0; i < arguments.length; i++) {
        var arg = arguments[i]

        if (!arg) continue
        if (typeof arg === 'string' || typeof arg === 'number') {
            this[arg] = true
        } else if (typeof arg === 'string') {
            if (/^\S+$/g.test(arg)) {
                this[arg] = true
            } else {
                arg = arg.split(" ")
                for (var j = 0; j < arg.length; j++) this[arg[i]] = true
            }
        } else if (Array.isArray(arg)) {
            if (arg.length) writeClasses.apply(this, arg)
        } else if (typeof arg === 'object') {
            for (var key in arg) {
                if (hasOwn.call(arg, key) && arg[key]) {
                    writeClasses.call(this, key)
                }
            }
        }
    }
}

function classNames() {
    var classes = Object.create(null)

    writeClasses.apply(this, arguments)
    return classes
}