My opinion of the code is this. It's pretty tight, which I can respect. I haven't run it, but it PROBABLY works. But it's hard to read. Things are n

My opinion of the code is this. It's pretty tight, which I can respect. I haven't run it, but it PROBABLY works. But it's hard to read. Things are named poorly. Many edge cases are missed (not checking args properly). These functions are not pure and therefore, harder to test. Maybe true 1337 H@X0Rz don't need to write tests, but some of us have mortgages to pay... I didn't re-write all of this mess, but check out the few util functions that I re-wrote. As a developer, which version would you rather work with? If you said the original version that's cool with me. But don't try to come work on my team. // isNull :: a -> Boolean const isNull = x => x == null // isNullOrEmpty :: String -> Boolean const isNullOrEmpty = string => string == null || !string.length // $ :: String -> HTMLDocument -> HTMLElement const $ = (id, _document = document) => { if (isNullOrEmpty(id)) return null if (isNull(_document)) return null return _document.getElementById(id) || null } // findClassInElement :: HTMLElement -> String -> [HTMLElement] const findClassInElement = (el, className) => { if (isNull(el)) return [] if (isNullOrEmpty(tagName)) return [] return el.getElementsByClassName(className) || [] } // findTagInElement :: HTMLElement -> String -> [HTMLElement] const findTagInElement = (el, tagName) => { if (isNull(el)) return [] if (isNullOrEmpty(tagName)) return [] return el.getElementsByTagName(tagName) || [] } // findClass :: String -> HTMLDocument -> [HTMLElement] const findClass = (className, _document = document) => { if (isNullOrEmpty(className)) return [] if (isNull(_document)) return [] return findClassInElement(_document, className) || [] } // elementHasClass :: HTMLElement -> String -> Boolean const elementHasClass = (el, className) => { if (isNull(el)) return false if (isNullOrEmpty(className)) return false return el.className.includes(className) } // addClass :: HTMLElement -> String -> Boolean const addClass = (el, className) => { if (isNull(el) || isNull(el.className)) return false if (isNullOrEmpty(className)) return false if (el.className.includes(className)) return true el.className = `${el.className} ${className}` return true }