class/class_backend/node_modules/tar/lib/strip-trailing-slashes.js

// warning: extremely hot code path.
// This has been meticulously optimized for use
// within npm install on large package trees.
// Do not edit without careful benchmarking.
module.exports = str => {
  let i = str.length - 1
  let slashesStart = -1
  while (i > -1 && str.charAt(i) === '/') {
    slashesStart = i
    i--
  }
  return slashesStart === -1 ? str : str.slice(0, slashesStart)
}