Nodejs difference between two paths

Question

I am trying to get the difference between two path. I've come with a solution, but I am not really happy about it, even if it works. Is there a better / easier way to do this?

var firstPath =  '/my/first/path'
  , secondPath = '/my/first/path/but/longer'

// what I want to get is: '/but/longer'

// my code:
var firstPathDeconstruct = firstPath.split(path.sep)
  , secondPathDeconstruct = secondPath.split(path.sep)
  , diff = []

secondPathDeconstruct.forEach(function(chunk) {
  if (firstPathDeconstruct.indexOf(chunk) < 0) {
    diff.push(chunk)
  }
})

console.log(diff)
// output ['but', 'longer']

Answer 1

Node provides a standard function, path.relative , which does exactly this and also handles all of the various relative path edge cases that you might encounter:

From the online docs :

path.relative(from, to)

Solve the relative path from from to to .

Examples:

 path.relative('C:\\\\orandea\\\\test\\\\aaa', 'C:\\\\orandea\\\\impl\\\\bbb') // returns '..\\\\..\\\\impl\\\\bbb' path.relative('/data/orandea/test/aaa', '/data/orandea/impl/bbb') // returns '../../impl/bbb' 

Answer 2

This may work. Although it relies on the fact that it knows which of them is a subset of the other, and assumes case will be the same.

var diff = secondPath.substring(firstPath.length);