router-navigation.js

function main (sources) {
  
  let {DOM} = sources
  
  function preventDefault (e) {
    
    e.preventDefault()
    return e
  }
  
  let routeTo$ = DOM.select('a').events('click')
    .filter(e => e.target.getAttribute('href') && !e.target.getAttribute('target'))
    .map(preventDefault)
    .map(e => e.target.getAttribute('href'))
  
  return {
    router: routeTo$
  }
}