golfed-jquery-like.babel.js

// @jsxFactory: $create

// untested yet
const D=document,Arr=(a,b,e) => Array.prototype.slice.call(a,b,e)
      
export $ = (s,r=D) => r.querySelector(s)
export $$ = (s,r=D) => Arr(r.querySelectorAll(s))
export $create = (t,p={},c,el) => (
  el=D.createElement(t),
  Object.keys(p).forEach(k=>el.setAttribute(k,p[k])),
  c&&(Array.isArray(c)?c:[c]).forEach(n=>el.appendChild(n.nodeType?n:D.createTextNode(n))),
  el
)

export $walk = (el,f,cb)=>!f?null:el.childNodes.forEach(n=>n.nodeType==1?$walk(n,f,cb):cb?f(n)&&cb(n):f(n))

golfed-jquery-like.js

// @jsxFactory: $create

var D=document,Arr=function(a,b,e){return Array.prototype.slice.call(a,b,e)}

function $(s,r){r=r||D;return r.querySelector(s)}
function $$(s,r){r=r||D;return r.querySelectorAll(s)}
function $create(t,p,c){p=p||{};var el=D.createElement(t)
	Object.keys(p).forEach(function(k){el.setAttribute(k,p[k])})
	c&&(Array.isArray(c)?c:[c]).forEach(function(n){el.appendChild(n.nodeType?n:D.createTextNode(n))})
	return el
}

function walkInDOM(elem, filterOrCallback, maybeCallback) {
  // don't walk mindless
  if(!filterOrCallback) return;

  elem.childNodes.forEach(function(node){
    return node.nodeType===1
      ? walkInDOM(node, filterOrCallback, maybeCallback)
      // if you have a callback, you have a filter
      : maybeCallback
        // if filter return true, callback
        ? filterOrCallback(node) && maybeCallback(node)
        // else, just callback
        : filterOrCallback(node)
  })
}

ideas for events lib.js

E(window, 'bs-style-event')
E($('form'), 'submit')

Ewhen( $('form'), 'submit', doShit )
Ewhen( window, { beforeunload: doShit, onload: doShit} )
Ewhen( $$('button'), ['click', 'keypress'], doShit )

Can do:
$(selector) to get one element
$$(selector) to get a array of elements
$create(tagName, attributes, children) to create elements

$('body').appendChild($create('ul', {class:'list-of-menu'}, [
  $create('li',{},'1st menu'),
  $create('li',{},'2nd menu'),
  $create('li',{},'3st menu')
]))