Select multiple elements and receive an array

select.js

const select = (query, elem = null) => {

	elem = (elem==null ? document : elem)

	let elems = elem.querySelectorAll(query)

	if (elems==null) return []
	else             return Array.prototype.slice.call(elems, 0)

}

Example:

select('a') // [<a>, …]
select('img') // [<img>, …]
select('img', select('p')) // [<img>, …]