join with normalize

1.js

const benchmark = require('benchmark');
const suite = new benchmark.Suite;

const join = require('path').join;
const normalize = require('path').normalize;

const p = '/ddd/../../../aaa/bbb/ccc';

function getRandomStr() {
  return '__' + Math.floor(Math.random() * 16777215).toString(16) + '__';
}

const judgeString = getRandomStr();

function isSafePath(path, ctx) {
  if (join(judgeString, path).indexOf(judgeString) === -1) {
    return false;
  }
  return true;
};

function isSafePath2(path, ctx) {
    path = path.slice(1);
    return normalize(path).startsWith('../');
};


// add tests 
suite.add('join#test', function() {
  isSafePath(p);
})
.add('normalize#test', function() {
  isSafePath2(p);
})
// add listeners 
.on('cycle', function(event) {
  console.log(String(event.target));
})
.on('complete', function() {
  console.log('Fastest is ' + this.filter('fastest').map('name'));
})
// run async 
.run({ 'async': true });