helper.js

function logText(text) {
  const elPre = document.createElement('PRE')
  const elCode = document.createElement('CODE')
  elPre.innerHTML = text
  elCode.appendChild(elPre)
  document.body.appendChild(elCode)
}

var text = "\
page 1\n\
  page 1.1\n\
  page 1.2\n\
    page 1.2.1\n\
page 2\n\
page 3\n\
  page 3.1\n\
  page 3.2\n\
page 4\n\
  page 4.1\n\
    page 4.1.1\n\
      page 4.1.1.1\n\
  page 4.2\n\
page 5\
"

logText(text)