const $$ = ( selector, context = document ) => {
  const regex = /^#/g
  const elements = context.querySelectorAll( selector )

  return ( regex.test( selector ) )
            ? elements[ 0 ]
            : elements
}

$$( '#myjQuery' ).innerHTML = $$( 'div' ).length
$( '#jQuery' )[ 0 ].innerHTML = $( 'div' ).length