failback-parse-error.js

var name = 'foo\\\\-bar'
var failbackExpr = /(\\*)-/g
var failbackMatch
var failback
while ((failbackMatch = failbackExpr.exec(name))) {
  esc = failbackMatch[1]
  esc = esc.length && esc.length % 2
  if (esc) continue
  failback = name.slice(failbackMatch.index + 1)
  name = name.slice(0, failbackMatch.index)
  break
}

console.log({name, failback})
// { name: 'foo', failback: '\\-bar' }