listing-2.js

var lines = layout.split(/[\r\n]/) // split layout into individual lines
  .map(
  i=>i.match(/\+/)? // '+' means one or more boxes ending
  i.split(/[\+\|]/)
  .filter(e=>e)     // filter out zero length lines
  .map(
              b=>b.match(/^\-+$/)? // all '-'s mean box is ending here
              -(b.length+1):       // denote that by -ve number
              b.length+1)          // box still open. put +ve length
  :i.split(/\|/)              // if '+' not found, then split at '|'
  .filter(e=>e)               // filter out zero length lines
  .map(b=>b.length+1))        // put box width in the array
  .filter(e=>e.length);       // filter out empty arrays